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Briefing Document & Podcast – Greece E‑Invoicing, E‑Reporting, and E‑Transport: Scope, Timeline & Requirements

2 weeks ago
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Last Update: February 18, 2026

Executive Summary

Greece has implemented a comprehensive e-invoicing and e-reporting framework, known as the myDATA (My Digital Accounting and Tax Application) system, to combat tax evasion and modernize VAT administration. Launched in 2020, myDATA requires businesses to digitally report all sales and purchase invoices in real-time or near real-time. Since 2024, the system is fully enforced, with penalties for non-compliance and the introduction of pre-filled VAT returns based on myDATA data.

While B2G (Business-to-Government) e-invoicing became mandatory in phases, completing by January 1, 2025, Greece is now introducing a phased mandatory B2B (Business-to-Business) e-invoicing requirement in 2026. Large taxpayers (2023 revenues > €1 million) must adopt e-invoicing by March 2, 2026, with a transition period until May 3, 2026. All other businesses must comply by October 1, 2026, with a transition until December 31, 2026. This mandate, authorized by the EU Council, applies broadly to almost all transactions and taxable persons in Greece.

The system operates on a “clearance” model, where invoice data must be transmitted to the tax authority (AADE) for validation and assignment of a unique “MARK” before the invoice is considered valid. Significant penalties are in place for non-compliance, including fines up to 50% of the undeclared VAT. The Greek government has provided support measures, such as free e-invoicing tools and financial incentives, particularly for Small and Medium-sized Enterprises (SMEs).

1. Scope of the Mandate

The Greek e-invoicing and e-reporting mandate is exceptionally broad, covering nearly all transactions and taxable persons under Greek VAT.

  • Domestic B2B (Business-to-Business):E-reporting: Mandatory since 2021 for all sales and purchase invoices.
  • E-invoicing: Will become mandatory in a structured electronic format from March 2, 2026, for large taxpayers, and October 1, 2026, for all other businesses. Traditional paper invoices will no longer be compliant for B2B transactions.
  • Domestic B2C (Business-to-Consumer):E-reporting: Mandatory. Sales data must be sent electronically to AADE (via fiscal cash registers or myDATA portal).
  • E-invoicing: Remains optional; businesses can issue paper receipts, but sales data reporting is compulsory. Online cash registers (FIMs) transmit each transaction in real-time.
  • Domestic B2G (Business-to-Government):E-invoicing: Mandatory since January 1, 2025, for all invoices issued to Greek public sector entities. Suppliers must use the EN 16931 European standard (typically Peppol BIS 3.0 UBL format), delivered via a central Interoperability Center.
  • Intra-EU B2B Supplies (Sales to EU buyers):E-reporting: Mandatory for Greek sellers via myDATA.
  • E-invoicing: Optional. Greek companies are not legally compelled to send e-invoices to EU customers due to EU VAT Directive requirements, often continuing to use PDFs or paper invoices.
  • Intra-EU Acquisitions (Purchases from EU suppliers):E-reporting: Mandatory for Greek buyers, who must self-report transaction details and self-assess Greek VAT (reverse charge) in myDATA.
  • Imports & Exports (Transactions with Non-EU Countries):Exports: In scope for e-reporting, and e-invoicing will be required from 2026 as part of the B2B mandate. The invoice must be cleared through AADE’s system.
  • Imports: Greek importers must report purchases from non-EU suppliers via myDATA by entering a purchase invoice record.
  • Cross-border B2B Services:E-reporting: Mandatory. Greek suppliers must report services to clients abroad in myDATA. Greek recipients of services from foreign providers (subject to reverse charge) must record these in myDATA via a self-billing or “reverse charge invoice” entry.

Special Scenarios: The myDATA system encompasses complex scenarios such as self-billing, triangular transactions, chain transactions, and supplies under special VAT schemes (e.g., margin schemes). “There are no blanket exemptions for these cases – instead, each transaction must be appropriately classified and reported according to its VAT treatment.”

2. Taxable Persons in Scope

  • Domestic Businesses: All legal entities and individuals established or VAT-registered in Greece are subject to myDATA e-reporting. This includes businesses of all sizes and sectors, with “no broad exemptions for specific industries or for SMEs.”
  • A notable exception: enterprises with annual turnover below €10,000 can opt out of the VAT system and are therefore not required to report sales on myDATA.
  • Non-Established Entities: Foreign companies without a fixed establishment (FE) in Greece are not directly covered by the B2B e-invoicing mandate. While they must comply with Greek VAT reporting (e.g., via returns), they are not onboarded to myDATA for real-time reporting. If a foreign business has a branch or FE in Greece, that local entity is subject to myDATA and e-invoicing.
  • Voluntary Early Adopters: Greece offered incentives for voluntary adoption of e-invoicing prior to the mandate. By February 2026, “around 34,000 out of 38,000 large enterprises in Greece had already activated an e-invoicing solution ahead of the deadline,” demonstrating strong uptake.

3. Implementation Timeline

Greece’s digital reporting journey has progressed through several legislative milestones:

  • 2019: Law 4601/2019 transposed the EU Directive on e-invoicing for public procurement.
  • 2020: Law 4646/2019 introduced tax incentives for voluntary B2B e-invoicing. AADE Decision A.1138/2020 launched the myDATA e-books scheme.
  • 2021: Transmission of summary invoice data to myDATA became mandatory for all companies (phased start).
  • 2023: EU approval for domestic B2B e-invoicing (Implementing Decision (EU) 2023/593). B2G e-invoicing became operational for certain central government agencies. Law 5073/2023 reinforced myDATA enforcement and signalled B2B e-invoicing.
  • 2024: Full enforcement of digital reporting took effect from January 1, 2024. Penalties for non-compliance began. Pre-filled VAT returns based on myDATA data were introduced. Mandatory B2G e-invoicing across all government agencies became compulsory by January 2025.
  • 2025: Legal basis for mandatory B2B e-invoicing finalized. Joint Decision A.1128/2025 outlined the B2B mandate’s scope and timeline: February 2, 2026 for large taxpayers and October 1, 2026 for others.
  • 2026: On February 17, 2026, an extension was announced: large enterprises must now begin mandatory e-invoicing by March 2, 2026, with a “gradual implementation period” until May 3, 2026. Phase 2 (for SMEs and other businesses) remains scheduled for October 1, 2026, with a transition until December 31, 2026.

4. Technical & Functional Requirements

  • E-Invoice Format: All B2B and B2G e-invoices must be in a structured format compliant with the European Standard EN 16931. For B2G, Peppol BIS 3.0 UBL (XML) is standard. For B2B, e-invoices are generated as XML or JSON files containing all legally required data. Greece “does not require electronic invoices to be digitally signed or sealed” if transmitted through a certified channel.
  • E-Reporting Data and Validation: “Key data from the invoice must be transmitted to the AADE via the myDATA platform.” This process involves summarizing each invoice with specific information and using predefined codes for transaction types and tax categories. The transmitted data undergoes automatic validation.
  • Clearance and “MARK”: “Only a successfully validated invoice receives a MARK (clearance approval) from the tax authority.” This unique identifying code and a QR code (often included on the invoice) serve as proof of registration and integrity.
  • Real-Time Reporting: The system operates as a real-time clearance model. Sales invoices “should be transmitted to AADE at the moment of issuance or very shortly thereafter.” For technical failures, submission must occur “no later than the next day after issuance.”

5. Transmission & Workflow

  • Invoice Clearance Process: For B2B, the supplier must transmit the e-invoice data to AADE for approval in conjunction with delivering it to the buyer. This process is often instantaneous, with the supplier’s software sending data via API to myDATA, which validates and returns the MARK. Buyers are legally required to accept e-invoices. If a buyer does not see a purchase invoice in myDATA, they are expected to self-report the transaction to avoid VAT credit disallowance, which flags the non-compliant supplier.
  • Channels for Submission:Certified E-Invoicing Service Providers: Accredited private companies (“Hyphen-e” or ΥΠΑΗΕΣ) issue invoices on behalf of suppliers and handle clearance. Mandatory for B2G (or state portal).
  • AADE’s Free Platforms: “Timologio” (web portal) and myDATA app enable small businesses to create and send compliant e-invoices directly.
  • ERP/Accounting Software Integration: Businesses can use their existing systems to send invoice data via the myDATA REST API.
  • Deadlines for Transmission: Sales invoices are expected to be sent immediately upon issuance or by the next day. Purchase/expense records must be reported by the buyer if the supplier fails to do so by the VAT filing deadline.

6. Self-Billing

Self-billing is permitted in Greece but is subject to the same e-invoicing and reporting requirements. A self-billed invoice for domestic B2B transactions must be generated through a certified provider or the AADE portal to be valid. The buying company (issuer) must transmit the invoice data to myDATA and obtain a “MARK,” with a special document type code. Once cleared, it is recorded in both the buyer’s and supplier’s myDATA accounts.

7. Triangulation & Special Scenarios

  • Triangulation (Three-Party EU Trades): Each Greek entity involved must report its part of the transaction in myDATA using correct codes (e.g., intra-Community supply, intra-Community acquisition, reverse charge).
  • Chain Transactions: Greek taxpayers must report any invoice issued or received in a chain transaction with appropriate coding.
  • Cross-Border Reverse Charge: Greek buyers receiving services from foreign suppliers (subject to reverse charge) must self-issue a myDATA record for VAT purposes, indicating it as an incoming self-assessed invoice.
  • Zero-Rated & Exempt Supplies: All VAT-exempt or zero-rated transactions must be reported in myDATA with appropriate classification codes. “No category of taxable transaction is entirely carved out of Greece’s digital reporting.”

8. Archiving & Retention

Greek regulations require invoices and accounting records to be stored for at least five full years from the end of the fiscal year. E-invoices must be archived in their original structured format (XML/JSON) to preserve integrity. The myDATA platform retains submitted data, but taxpayers must maintain their own compliant archives. Records must remain readable and accessible for tax auditors.

9. Penalties & Enforcement

Greek authorities have significantly strengthened penalties for non-compliance.

  • Failure to Issue an E-Invoice (when required): If a mandatory e-invoice is not issued (e.g., a paper invoice used after the 2026 deadline), it’s treated as if no invoice was issued.
  • VAT-taxable transactions: Penalty of 50% of the VAT that would have been due.
  • Non-taxable/exempt transactions: Flat fine of €500 (single-entry books) or €1,000 (double-entry books) per audit per unissued invoice.
  • Failure to Report/Transmit Invoice Data (e-Reporting Violations):Unreported invoices: Fines equal to 10% of the transaction’s value, capped at €1,000 per invoice per day.
  • Late reporting: Reduced penalty of 5% of the transaction’s value.
  • Under-reporting: Penalty of 5% of the undeclared amount.
  • Other Non-Compliance: Flat fines for failing to transmit other accounting documents (€250/€500 per tax period). Repeated violations can double or quadruple fines.
  • Enforcement: AADE uses data analytics from myDATA to identify discrepancies, triggers audits, and flags VAT returns that don’t align with myDATA records. “The primary ‘penalty’ for non-compliant taxpayers is often the denial of VAT deductions or delays in VAT refunds until corrections are made.”

10. Pre-Filled VAT Returns

Greece has implemented pre-filled VAT returns using data from myDATA e-books since 2023. The AADE automatically calculates amounts for VAT return fields. While initial flexibility allowed for some deviation, the “intention is to phase out these tolerances and require that VAT returns exactly match the myDATA figures.” Taxpayers must correct the underlying myDATA reports if discrepancies exist, rather than overriding the return. This system is a cornerstone of Greece’s digital tax strategy, aiming for near-automatic VAT returns in the future.

11. Impact on SMEs and Startups

  • Compliance Burden vs. Benefits: All VAT-registered SMEs must use myDATA and e-invoicing from late 2026. While initial administrative workload is expected, long-term benefits include reduced errors, faster VAT refunds, and simplified filings.
  • Support Measures:Phased Rollout: SMEs have an additional 8-month period (until October 2026) compared to large companies.
  • Free Tools: AADE’s “Timologio” portal and myDATA mobile app cater specifically to SMEs.
  • Financial Incentives: Tax incentives for early adopters include super-deduction of 100% of e-invoicing expenses, faster VAT refunds (within 45 days), and a reduced statute of limitations for tax audits (3 years instead of 5).

Conclusion and Correction Mechanisms

Greece’s myDATA system represents a comprehensive, real-time VAT control framework. The phased mandatory e-invoicing for B2B (starting March 2, 2026, for large companies and October 1, 2026, for others) combined with existing e-reporting obligations, ensures nearly every transaction is digitally visible to the tax authority.

For corrections, “if an issued e-invoice contains errors or needs adjustment, the correction is typically made by issuing a corrective document (credit note or debit note) referencing the original invoice.” If data was missing or wrong, it should be fixed in myDATA as soon as possible. “Prior to the VAT return filing, taxpayers can update their myDATA submissions without formal penalties.” Buyers can “self-report” supplier invoices not in their myDATA records, protecting their VAT deduction and flagging non-compliant suppliers. Businesses are advised to implement robust internal controls and utilize myDATA’s correction features to proactively ensure compliance and avoid significant penalties.

Source of Information: The information presented in this briefing document is derived from the provided excerpts from “Briefing Document & Podcast – Greece E‑Invoicing, E‑Reporting, and E‑Transport: Scope, Timeline & Requirements – VATupdate” (last updated February 18, 2026). Additional context regarding VATupdate.com’s role as an information hub was noted from “New Note”.

Detailed version

Greece’s e‑invoicing and e‑reporting framework (the myDATA system) applies broadly to almost all transactions and taxable persons, with a phased mandatory rollout in 2026 and updated deadlines as of February 2026. The Greek government’s myDATA (My Digital Accounting and Tax Application) platform, launched in 2020, requires businesses to digitally report all sales and purchase invoices in real-time (continuous transaction controls) as part of a national effort to combat tax evasion and modernize VAT administration. Since 2021, reporting of invoice data to the tax authorities has been obligatory for all Greek VAT-registered entities, and since 2024 the system is fully enforced with penalties for non-compliance. Electronic invoicing (structured digital invoices) has so far been mandatory for B2G (business-to-government) transactions and voluntary for B2B, but **Greece is now introducing a phased mandatory B2B e-invoicing requirement in 2026. (This was authorized by the EU Council in 2023, allowing Greece to derogate from the VAT Directive to impose domestic B2B e-invoicing.) Large taxpayers (2023 revenues > €1 million) must adopt e-invoicing by March 2, 2026 (with a short transition to May 2026), and all other businesses by October 1, 2026. The myDATA system pre-fills VAT returns based on reported data – since 2024, the tax authority auto-calculates VAT declarations and is phasing out any manual adjustments. The sections below provide a comprehensive analysis of the Greek e‑invoicing and e‑reporting regime (updated as of February 18, 2026), with references to the latest legislation, official publications, and expert commentary. [vatupdate.com] [vatupdate.com], [vatupdate.com] [vatupdate.com], [vatupdate.com] [vatupdate.com], [vatupdate.com] [vatupdate.com]

1. Scope of the Mandate

Transactions Covered: The Greek e‑invoicing and e‑reporting mandate covers all types of transactions by businesses under Greek VAT, with few exceptions. In summary, the scope includes:
  • Domestic B2B (Business-to-Business): All sales of goods or services between Greek VAT-registered businesses must be reported to the myDATA platform, and each B2B invoice issued in Greece must be transmitted electronically to the tax authority for validation (clearance). From 2026, domestic B2B invoices must also be issued in a structured electronic format (first for large companies, then all businesses; see Section 3: Implementation Timeline). Until the e-invoicing mandate’s start date, businesses may still issue paper or PDF invoices to domestic partners, but reporting the invoice data to myDATA is compulsory and a condition for VAT deduction. Once e-invoicing is in force, traditional paper invoices will no longer be considered compliant for B2B transactions. [vatupdate.com], [vatupdate.com] [vatupdate.com], [vatupdate.com] [vatupdate.com] [vatupdate.com]
  • Domestic B2C (Business-to-Consumer): Sales to non-taxable persons (consumers) are included in the e‑reporting system, but not subject to mandatory structured e‑invoice issuance. Businesses must still record all retail sales either through fiscal cash registers connected to AADE or by reporting summary invoices/receipts via myDATA. As of 2024, online cash registers (FIMs) must transmit each transaction in real time to AADE. E-invoicing for B2C remains optional – businesses can issue paper receipts or simplified invoices to consumers, but the sales data must be sent electronically to the tax authority (usually via the cash register or the myDATA portal). B2C transactions are thus within the e-reporting scope even though consumers are not required to receive structured e-invoices. [vatupdate.com] [vatupdate.com]
  • Domestic B2G (Business-to-Government): **Electronic invoicing is mandatory for all invoices issued to Greek public sector entities (B2G). Greece implemented B2G e-invoicing in phases: starting with large central government bodies in 2023 and extending to all public sector contracts by January 1, 2025. Suppliers must issue e-invoices in the EN 16931 European standard (often via the Peppol network) for public procurement contracts, and these invoices are delivered through a central platform (the Interoperability Center, connected to Peppol) to the contracting authority. In addition, B2G invoice data must be reported to myDATA for tax records (usually handled by the same certified provider or the government “timologio” system at the time of issuance). (Note: Low-value government purchases and certain sensitive contracts may be exempt from B2G e-invoicing, but these are limited exceptions.) [vatupdate.com] [vatupdate.com], [vatupdate.com] [vatupdate.com]
  • Intra‑EU B2B Supplies (Sales to EU buyers): These cross-border B2B sales by Greek businesses must be reported to myDATA as part of the seller’s revenue records. However, issuing a structured e-invoice for intra-EU B2B transactions remains optional under the Greek mandate. Greek companies may use the same e-invoicing infrastructure for EU sales (and many do so for convenience), but they are not legally compelled to send e-invoices to EU-based customers because the EU VAT Directive requires mutual agreement on electronic invoices for intra-Community trade. In practice, Greek suppliers often continue to send PDFs or paper invoices to EU customers, but still must transmit the invoice data to the AADE via myDATA. (If a Greek company does choose to issue an e-invoice to an EU customer, the EU buyer can decide whether to accept it or request a traditional format.) [vatupdate.com] [vatupdate.com], [sovos.com] [vatupdate.com]
  • Intra‑EU Acquisitions (Purchases from EU suppliers): Purchases by Greek businesses from suppliers in other EU countries are also within the e-reporting scope. Because the foreign seller is not on the Greek myDATA system, the Greek buyer must self-report the transaction details into myDATA. Typically, the buyer records an incoming invoice in myDATA as an intra-Community acquisition, including the foreign supplier’s VAT number and the net amount; the system then reflects the Greek VAT self-assessment (reverse charge) for that purchase. These transactions are also still reported via European Sales Listing (VIES) for EU cross-checking, but Greece’s aim is to eventually rely on myDATA for much of this reporting. [vatupdate.com]
  • Imports & Exports (Transactions with Non-EU Countries): Exports from Greece to non-EU buyers are in scope for e-reporting and e-invoicing, similarly to domestic sales. From 2026, Greek companies will be required to issue e-invoices for exports to non-EU customers (as part of the B2B mandate). If a non-EU customer cannot accept the structured invoice, the Greek seller may provide a human-readable version (e.g., PDF), but the invoice must still be cleared through AADE’s system when issued. Imports (purchases by Greek companies from non-EU suppliers) must be reported by the Greek importer via myDATA, generally by entering a purchase invoice record with relevant import information. Customs imports involve additional electronic declarations (through the ICISnet customs system), but the taxable person must also ensure the accounting entry for the import (or any self-issued import invoice for VAT purposes) is recorded in myDATA to complete the e-books. [vatupdate.com]
  • Cross‑border B2B Services: Services provided by Greek companies to clients abroad (whether EU or non-EU) are treated as zero-rated exports for VAT and must be reported in myDATA by the Greek supplier (with an appropriate tax classification code indicating “out of scope” or reverse-charge, depending on the case). Conversely, services received by a Greek business from a foreign provider (where Greek VAT applies via reverse charge) must be recorded in myDATA by the Greek recipient, effectively via a self-billing or “reverse charge invoice’’ entered into the system. The self-assessed VAT on such services is calculated within the system for inclusion in the VAT return. These cross-border B2B services are not subject to the Greek e-invoice format requirement (the foreign supplier’s document can be non-electronic), but the Greek recipient’s reporting of the transaction is required for VAT compliance. [vatupdate.com]
Inclusion of Special Scenarios: The Greek e-invoicing/e-reporting rules encompass special invoicing scenarios as well: Self-billing, triangular transactions, chain transactions, and sales under special VAT regimes are all required to be reported via myDATA. There are no blanket exemptions for these cases – instead, each transaction must be appropriately classified and reported according to its VAT treatment. For example, self-billed invoices (invoices issued by the buyer on behalf of the supplier) are permitted in Greece, but the buyer-issuer must send those invoices to myDATA just like any other sale, tagging them as self-billing documents (see Section 6). Triangulation and chain transactions do not escape reporting; each leg of the transaction is reported by the Greek party involved, using special codes to denote intra-EU dispatches, acquisitions, or domestic reverse charges as applicable (see Section 7). Likewise, supplies under special VAT schemes (e.g. travel agency margins, second-hand goods, agricultural flat-rate farmers, etc.) must be invoiced and reported; the invoices need to carry any legally required notation (e.g. “margin scheme – VAT not shown”) and the myDATA submission uses special tax codes to indicate the nature of these supplies. [vatupdate.com]

2. Taxable Persons in Scope

Domestic Businesses: All legal entities and individuals established or registered in Greece for VAT are subject to the myDATA e-reporting obligations. This includes Greek companies of all sizes, sectors, and accounting regimes (both double-entry and single-entry taxpayers) – there are no broad exemptions for specific industries or for SMEs. Any business issuing invoices under the Greek Accounting Standards (Law 4308/2014) must comply with digital reporting. Even newly established micro‑enterprises are expected to use the system (with free tools available to simplify compliance). However, Greece has introduced a special VAT registration exemption for very small businesses: as of 2024, domestic enterprises with annual turnover below €10,000 can opt to remain outside the VAT system (per Article 39 of the VAT Code, as amended). Such businesses (analogous to the EU’s SME exemption) do not charge VAT or file VAT returns, and thus they are not required to report sales on myDATA either. Aside from this voluntary small-business regime and a few sector-specific timing delays during rollout (see below), virtually all Greek-established VAT entities are in scope. [vatupdate.com], [vatupdate.com] [vatupdate.com]
Non-Established Entities: Foreign companies without a fixed establishment in Greece are not directly covered by the B2B e‑invoicing mandate. The 2023 EU Council decision authorizing Greece’s e-invoicing specifically limits the mandate to resident taxable persons. Therefore, a non-established company (one with no Greek establishment) that is merely VAT-registered in Greece (for example, under the OSS/IOSS schemes or for occasional transactions) is not forced to issue Greek e-invoices. Such companies do still have to comply with any applicable VAT reporting via returns or OSS, but they are not on-boarded to myDATA for real-time reporting. (If a foreign business does have a branch or fixed establishment in Greece, that local establishment is considered a Greek entity for these purposes and must use myDATA and e-invoices like any other domestic business.) Foreign companies dealing with Greek buyers can voluntarily use Greek e-invoices (for instance, to facilitate the buyer’s compliance), but the Greek rules cannot compel a foreign business to adopt e-invoicing unilaterally. [vatupdate.com]
Special Situations & Optional Participation: There are a few particular cases regarding scope:
  • VAT Groups & Tax Representatives: Greece does not have a VAT grouping regime, and the obligations apply at the level of each registered entity. Tax representatives (for non-EU companies) or fiscal agents must ensure that the transactions of their principals are reported to myDATA if the principal is registered for VAT in Greece. The representative can use the myDATA platform on behalf of the foreign entity, but the foreign entity itself isn’t obliged to use Greek e-invoicing.
  • Government Agencies & Public Bodies: Public sector entities (as buyers) have been required to register in the central e-invoicing platform to receive supplier e-invoices, but they do not issue invoices except in specific cases (self-billed invoices or refunds). When a public entity issues an invoice (e.g. recharging a cost), it is treated like a B2B supplier and must also report to myDATA. [vatupdate.com]
  • Voluntary Early Adopters: Prior to the mandate, using certified e-invoicing providers has been voluntary for B2B. To encourage this, Greece offered incentives (see Section 11): e.g. extra tax deductions and faster VAT refunds for companies that adopted e-invoicing early. Many businesses – including SMEs – took advantage of these benefits to start e-invoicing before the 2026 mandate. By February 2026, the Ministry of Finance reported that around 34,000 out of 38,000 large enterprises in Greece had already activated an e-invoicing solution ahead of the deadline, reflecting strong voluntary uptake. [vatupdate.com], [vatupdate.com] [vatupdate.com]

3. Implementation Timeline

Legislative Milestones: Greece’s e-invoicing and e-book regime was established through a series of laws and decisions since 2019:
  • 2019: Law 4601/2019 (April 2019) transposed the EU Directive 2014/55 on electronic invoicing in public procurement, requiring Greek public entities to accept e-invoices and paving the way for B2G e-invoicing. [vatupdate.com], [vatupdate.com]
  • 2020: Law 4646/2019 introduced tax incentives for voluntary B2B e-invoicing (100% additional deduction of e-invoicing costs, faster VAT refunds, shorter tax audit statute of limitations) effective from 2020–2022. In June 2020, AADE Decision A.1138/2020 launched the myDATA e-books scheme, mandating digital reporting of income/expense data. Pilot testing of myDATA occurred in H2 2020. [vatupdate.com], [vatupdate.com]
  • 2021: Law 4714/2020 and subsequent decisions delayed and refined the myDATA rollout due to COVID-19. As of October 2021, transmission of summary invoice data to myDATA became mandatory for all companies (with a phased start based on size). By November 2021, recording of purchase invoices (expenses) in myDATA also became mandatory.
  • 2022: Throughout 2022, the government issued technical updates and allowed a grace period for businesses to adjust. No financial penalties for late reporting were applied in 2021–22; the focus was on onboarding taxpayers and improving the system. Decision A.1090/2022 (August 2022) set the stage for real-time invoice reporting from 2023 and outlined enforcement rules. Also, in August 2022, Law 4972/2022 was passed, mandating phased B2G e-invoicing for public contracts starting in 2023. [vatupdate.com] [vatupdate.com]
  • 2023: By early 2023, Greece received EU approval (Council Implementing Decision (EU) 2023/593, March 2023) to require domestic B2B e-invoicing through end of 2024, later extended to 2026. In September 2023, initial steps of B2G e-invoicing became operational: certain central government agencies began accepting only e-invoices. Law 5036/2023 and Law 5073/2023 (December 2023) introduced anti-evasion measures, including final provisions for myDATA enforcement and signaling the upcoming B2B e-invoice mandate. AADE Decision A.1170/2023 (Oct 2023) updated the myDATA rules for 2024 onward, including the requirement that VAT returns align with myDATA and setting penalties for non-compliance. [vatupdate.com] [vatupdate.com], [vatupdate.com] [vatupdate.com]
  • 2024: Full enforcement of digital reporting took effect from January 1, 2024. All Greek businesses are now expected to transmit invoice data in real or near-real time (no later than the next day). The use of QR codes on invoices (linking to AADE’s database) became mandatory for validated invoices. Penalties for failing to report transactions or misreporting (under the Tax Procedure Code as amended) started to apply in 2024 (after previous grace periods). Also effective 2024, pre-filled VAT returns using myDATA data have been introduced (see Section 10). On the B2G side, from June 2024 all remaining public-sector entities were ready to receive e-invoices, and by January 2025 B2G e-invoicing across all government agencies became compulsory. [vatupdate.com] [vatupdate.com] [vatupdate.com]
  • 2025: The legal basis for mandatory B2B e-invoicing was finalized. On July 25, 2025, the Greek Parliament passed an amendment to Law 4308/2014 establishing that certain transactions must be invoiced electronically and empowering the Ministry of Finance and AADE to set the start dates by joint decision. Joint Decision A.1128/2025 (Sept 2025) was issued to outline the B2B mandate’s scope and timeline, and Decision A.1129/2025 provided technical details. The initial plan (announced September 2025) set February 2, 2026 as the start for large taxpayers and October 1, 2026 for all others, with transitional periods (to March 31, 2026 and Dec 31, 2026 respectively) during which dual systems could be used. Meanwhile, the new VAT Code (Law 5144/2024) took effect in January 2025, consolidating VAT rules (including the SME exemption regime and digital reporting obligations). [vatupdate.com], [vatupdate.com] [vatupdate.com] [vatupdate.com], [vatupdate.com]
  • 2026: In light of the upcoming mandate, authorities provided an additional short extension for large companies: A Joint Decision announced on February 17, 2026, postponed the Phase 1 e-invoicing go-live by one month. Large enterprises must now begin mandatory e‑invoicing by March 2, 2026, with a “gradual implementation period” running from March 2 to May 3, 2026 during which they can finalize technical integration while still using existing billing systems in parallel. By May 3, 2026, however, all their invoicing must be fully electronic. Phase 2 (for SMEs and other remaining businesses) remains scheduled to start on October 1, 2026 (with a transition until December 31, 2026) – any changes or confirmation of this second phase will be communicated by AADE in due course (as of Feb 2026, no change to Phase 2 dates has been announced). [vatupdate.com] [vatupdate.com]

4. Technical & Functional Requirements

E-Invoice Format: All B2B and B2G electronic invoices in Greece must be issued in a structured format compliant with the European Standard EN 16931. For B2G invoices, Greece uses the Peppol BIS 3.0 UBL format (a type of XML) as the standard, in line with EU requirements for public procurement. For B2B, the 2025 decisions (A.1128/2025 and A.1129/2025) mandate that e-invoices adhere to the same core EN 16931 content requirements. In practice, Greek e-invoices are generated as XML or JSON files containing all legally required invoice data. Each invoice must include the customary VAT content (seller and buyer details with Tax ID numbers, invoice date and unique number, description of goods/services, quantities, unit prices, tax base, VAT rate, VAT amount, and totals) as specified by Greek law (which mirrors EU VAT Directive rules). If the invoice falls under a special VAT treatment (e.g. reverse charge, exemption, margin scheme), that fact must be clearly indicated on the invoice (usually by referencing the relevant VAT law article). Notably, Greece does not require electronic invoices to be digitally signed or sealed, as long as they are transmitted through a certified channel or the state portal. Integrity and authenticity of origin are guaranteed by the controlled platform process: once an invoice is submitted to AADE, it receives a unique identifying code (known as a “MARK”) and a QR code, which serve as proof that the invoice data is registered and has not been altered. Businesses often include the QR code/registration number on the invoice sent to the buyer, so that the buyer (or a tax auditor) can scan it and retrieve the invoice report from AADE’s database in real time. [vatupdate.com] [vatupdate.com] [vatupdate.com], [vatupdate.com]
E-Reporting Data and Validation: When an invoice is issued, key data from the invoice must be transmitted to the AADE via the myDATA platform – this process is sometimes called “e-reporting” or the transmission of electronic books (eBooks) data. The myDATA schema requires summarizing each invoice with information such as: the unique invoice number and date, the VAT numbers of supplier and customer, the type of transaction (using a predefined code for the invoice type and tax category), net value of the supply, VAT rate(s) and amount(s), any exemptions or self-assessment indicators, and other specifics like withholding taxes or fees if applicable. The transmitted data is subject to automatic validation rules: for example, the system checks that calculations are consistent (correct VAT totals, etc.) and that required fields are present. If an error is detected (like an invalid VAT number or a mismatch in totals), the submission is rejected and must be corrected by the taxpayer. Only a successfully validated invoice receives a MARK (clearance approval) from the tax authority. The AADE then uses the incoming streams of invoice data to update two ledgers for each taxpayer: an income (sales) ledger and an expense (purchases) ledger in the myDATA “e-books”. Every reported invoice for which a taxpayer is the seller populates their sales ledger; if the taxpayer is the buyer, the transaction appears in their purchases ledger (either via the seller’s report or via the buyer’s own submission for imports/self-billing). The myDATA system imposes specific coding for different types of transactions (e.g. distinguishing retail receipts, invoices, credit notes, self-billed invoices, intra/EU sales, etc.), and businesses must ensure they use the correct codes so that the data feeds into the right sections of their ledgers. [vatupdate.com], [vatupdate.com] [vatupdate.com], [vatupdate.com] [vatupdate.com]
Real-Time Reporting and Data Elements: The Greek system is essentially a real-time clearance model – under current rules, sales invoices should be transmitted to AADE at the moment of issuance or very shortly thereafter. As of 2024, invoices generated through software must be sent immediately via the API, and retail cash registers transmit each receipt in real time to AADE’s server. The system previously allowed next-day (T+1) submission for B2B invoices, but that grace has largely been eliminated for most sectors. Some large utility and telecom companies received brief extensions to adapt their systems in early 2024, but those have expired. Now, the rule is that if live transmission fails due to technical issues, the data should be sent as soon as possible and no later than the next day after issuance. In addition, certain expense data (like payroll, asset depreciation, and other non-invoice accounting entries) can be reported on a periodic basis (e.g. monthly) rather than in real time – these entries are still part of the myDATA eBooks and are usually submitted by the time of the VAT return filing for the period. All data fields required for VAT compliance are captured by the system, enabling the tax authority to cross-validate transactions between sellers and buyers and to use the information for compliance and pre-filling of returns (see Section 10). [vatupdate.com]

5. Transmission & Workflow

Invoice Clearance Process: For B2B transactions, Greece’s model is a “clearance” e-invoicing system: the supplier must transmit the e-invoice (or at least its VAT-relevant content) to the AADE for approval in conjunction with delivering the invoice to the buyer. In practice, this is often instantaneous: the supplier’s software or service provider sends the invoice data via web API to the myDATA platform, which validates and returns the unique ID (MARK) and a QR code. Only then is the invoice considered cleared for tax purposes; the supplier typically provides the buyer with a copy of the e-invoice (as a PDF or structured file), including the QR or registration number as proof of clearance. For domestic B2B transactions between Greek firms, buyers are required to accept electronic invoices – once the mandate is active, a buyer cannot demand a paper invoice. (There is no separate “approval” step by the buyer on the platform; acceptance is implied by law.) The buyer will see the invoice appear in its myDATA purchase ledger automatically after the supplier’s submission. If the buyer does not see a particular purchase invoice in myDATA (e.g. because the supplier failed to report it), the buyer is expected to self-report the transaction by the deadline of the VAT return to avoid VAT credit disallowance. This mechanism creates a strong incentive for buyers to police their suppliers’ compliance, since any purchase invoice absent from myDATA cannot be used to support a VAT deduction. After the buyer self-reports, the supplier is flagged in the system and may be subject to audit or penalties for failing to report that invoice. [vatupdate.com] [vatupdate.com]
Channels for Submission: Taxpayers can choose different methods to transmit invoices and data to the AADE: [vatupdate.com], [sovos.com]
  • Certified E-Invoicing Service Providers (“Hyphen-e” or ΥΠΑΗΕΣ) – These are government-accredited private companies that issue invoices on behalf of suppliers and handle the clearance transmission automatically. Using an accredited provider is one of the two allowed ways to generate a compliant e-invoice. Providers must adhere to strict security and format standards set by AADE, and they facilitate both B2B and B2G flows. Many large companies contract providers for convenience; notably, for B2G invoices, the use of a certified provider (or the state portal) is mandatory to ensure Peppol connectivity. [vatupdate.com]
  • AADE’s Free Platforms (“Timologio” and “myDATA App”) – As an alternative, AADE offers a web portal called Timologio and a mobile application (myDATA app) that allow especially small businesses to create and send compliant e-invoices at no cost. These tools are directly connected to the myDATA system; when a business issues an invoice through Timologio or the app, the data is automatically transmitted and cleared. This option is intended for SMEs or freelancers with low invoice volume who may not have their own software. [vatupdate.com], [sovos.com]
  • ERP/Accounting Software Integration (API) – Businesses can also use their existing billing/ERP systems to send invoice data through the myDATA REST API. Many medium and large companies have updated their software (or use middleware) to automatically report invoices to myDATA in real time as they are generated. AADE has published detailed technical specifications (XSD schemas and API documentation) for software developers. Companies using this method must ensure their systems handle the required fields, error checks, and retrieval of the clearance codes. [vatupdate.com]
B2G Workflow: In B2G transactions, there is an additional step: electronic invoices to government entities travel via the national Peppol access point (Interoperability Center) after clearance. Typically, a supplier’s certified provider will first send the invoice to AADE to obtain the MARK, then forward the EN 16931-compliant invoice (in UBL format) through the Peppol network to the receiving government entity. The public entity’s systems will process the e-invoice and relay back a status (acceptance or rejection) through the same channel. This two-step ensures both the tax authority and the contracting authority receive the invoice data. Since 2023, thousands of Greek public sector entities have been onboarded to accept e-invoices in this way. [vatupdate.com], [vatupdate.com] [vatupdate.com], [vatupdate.com]
Deadlines for Transmission: The timeliness of reporting is strictly regulated:
  • Sales Invoices: As noted, these should be sent to myDATA essentially immediately upon issuance (or at most by the next day). Delays beyond the allowed window constitute a violation. When Phase 1 of B2B e-invoicing begins (March 2026), large companies will be expected to have their clearance process in place by that date; a short grace period until May 3, 2026 will allow final adjustments while still permitting use of old methods in parallel. After that, issuing a paper invoice (without clearance) when one is required is equivalent to not issuing an invoice at all (subject to penalties – see Section 9). [vatupdate.com] [vatupdate.com]
  • Purchases and Expense Records: For purchase invoices received from Greek suppliers, the onus is on the supplier to report them. However, if by the VAT filing deadline the supplier has not transmitted the invoice, the buyer must do so (as a self-issued record) to avoid losing the input VAT credit. Certain non-invoice documents (like adjusting accounting entries or non-VAT income) that companies must report to complete their e-books can be uploaded in bulk just before filing the VAT return. [vatupdate.com] [vatupdate.com]
  • Periodic Summaries: During the initial rollout (2021–2022), small businesses were allowed to submit some summaries on a monthly/quarterly basis. As of 2024, the expectation is that most data is real-time, with only a few exceptions. The system’s design goal is to minimize delays between transaction and reporting to near-zero.

6. Self‑Billing

Treatment under E‑Invoicing: Self-billing is permitted in Greece (where a buyer issues an invoice in the name of the supplier), but it is subject to the same e-invoicing and reporting requirements. The Greek VAT Code and bookkeeping law (Law 4308/2014) allow self-billing provided there is a prior agreement, and such invoices must contain an indication that they were issued by the recipient on behalf of the supplier. Under the e-invoicing mandate, self-billed invoices for domestic B2B transactions (once in effect) will need to be generated through a certified provider or the AADE portal in order to be considered valid. In practice, this means the buying company (the issuer of a self-billed invoice) must transmit the invoice data to the AADE’s myDATA platform and obtain a clearance MARK just as a regular supplier would. The self-billed invoice is then delivered to the supplier (e.g. via email or through the provider’s system) and is simultaneously recorded in both parties’ myDATA accounts – as a sale for the supplier and a purchase for the buyer. [vatupdate.com] [vatupdate.com], [vatupdate.com]
Reporting and Validation: From the perspective of the myDATA system, a self-billed invoice is simply an invoice submitted by the buyer/issuer. The buyer uses their own AADE credentials or provider service to send the invoice to the platform, with a special document type code marking it as a self-billing document. Once cleared, the supplier will see the transaction in their digital ledger. There is no additional “confirmation” step required from the supplier in the platform; acceptance is assumed since the supplier authorized the self-billing arrangement. However, the supplier should reconcile these entries and has the right to dispute any inaccuracies with the buyer offline (and if needed, make corrections via credit/debit notes). All the usual content requirements apply to self-billed invoices, and they must reference the VAT of both parties and satisfy Greek invoice rules. If a self-billed invoice is not processed through the mandated electronic system when it should be, it is treated as if no valid invoice was issued, exposing both parties to tax risks (e.g., the buyer’s VAT deduction could be disallowed and the supplier could be penalized for failure to issue an invoice). In summary, self-billing is allowed but does not exempt companies from using the e-invoicing and e-reporting platform – it simply changes who sends the data (the buyer instead of the seller). [vatupdate.com]

7. Triangulation & Special Scenarios

Triangulation (Three-Party EU Trades): Greece’s reporting requirements encompass triangular transactions. Each Greek entity involved in a multi-party chain must report its part of the transaction in myDATA, using the correct codes to reflect the nature of the supply. For example, if a Greek company is the intermediate seller in an EU triangulation (buying goods from, say, Germany to deliver to Italy), it will issue an invoice to the Italian customer without Greek VAT (annotated “Triangulation – Article 141 VAT Directive” on the invoice). In myDATA, the Greek company will classify this as an intra-Community supply (exempt with credit) and report the sale accordingly. Simultaneously, the Greek company’s purchase from the German supplier is an intra-Community acquisition, which it must report in myDATA as an expense subject to Greek reverse charge VAT. The myDATA system has specific tax codes to denote such transactions so that the VAT is handled correctly (in this case, the acquisition is flagged for reverse charge and the corresponding output and input VAT are recorded for the Greek buyer). The triangulation simplification (which avoids charging VAT through the chain) is respected, but all legs are visible in the digital records for audit purposes. [vatupdate.com]
Chain Transactions: Other chain transactions (e.g. four or more parties involved in a supply chain) are treated similarly – Greek taxpayers must report any invoice they issue or receive as part of a chain, with appropriate coding. There is no special exemption for chain transactions. For instance, if a Greek company sells goods to a domestic customer but the goods are delivered directly from an overseas affiliate, the Greek company’s sale is still reported (likely as a domestic sale or an export, depending on the billing flow) and the import or intra-EU acquisition by the Greek customer is also reported. The key is that VAT treatment must be correctly indicated (e.g., if the Greek seller never takes title to the goods on Greek territory, it might be an out-of-scope transaction for Greek VAT – but it should still be reported in myDATA with a code for “out of scope” supply). Greek guidance and the myDATA codebook provide for these scenarios, ensuring that even complex multi-party transactions are captured.
Cross-Border Reverse Charge: When a Greek business is the recipient of a service from an EU or non-EU supplier and the service falls under the reverse-charge mechanism, the Greek buyer must self-issue a document equivalent to an invoice for VAT purposes. This could be done by entering the transaction in myDATA as an incoming self-assessed invoice (with codes indicating it’s a foreign service subject to reverse charge). The system will record the transaction in both sales (as an “outgoing” reverse charge supply for the foreign seller, under the buyer’s account) and purchases (as a self-assessed acquisition for the buyer), generating both output and input VAT entries so that the VAT is accrued and reclaimed in the same return. Domestic reverse-charge scenarios (for example, supplies of scrap or certain building materials between Greek businesses) are handled in a similar way: the supplier’s invoice is reported with a tax code indicating “no VAT – reverse charge,” and the buyer’s ledger reflects the corresponding purchase with reverse charge VAT. [vatupdate.com]
Zero-Rated & Exempt Supplies: All VAT-exempt or zero-rated transactions must be reported in myDATA with the appropriate classification. If an invoice is issued for a zero-rated or VAT-exempt sale (like an export, an intra-EU supply, or a domestic exempt transaction such as medical services), the supplier’s invoice should mention the applicable VAT exemption clause as required by law, and in myDATA the transaction is labeled with a code for the type of exemption (e.g. “exempt under Article 39” for small farmers, “out-of-scope” for certain non-taxable transactions, etc.). This ensures that the tax authority can differentiate these supplies even though no VAT is charged. The myDATA system effectively replaces the need for separate domestic sales listing of exempt vs. taxable sales. Businesses under special schemes (e.g. travel agencies using the margin scheme, or investment gold sales) must also report their invoices; the system provides codes to indicate that no standard VAT is due (so that the prefilled return will not expect output tax on those sales). In short, no category of taxable transaction is entirely carved out of Greece’s digital reporting – the framework is comprehensive, with the onus on taxpayers to handle special cases via the proper notation and data fields. [vatupdate.com]

8. Archiving & Retention

Retention Period: Greek regulations stipulate that invoices and accounting records (including e-invoices and digital reports) must be stored for at least five full years from the end of the fiscal year they relate to. In certain cases (e.g. if a taxpayer’s income tax return remains subject to audit for up to 10 years), records may need to be kept longer, and many companies choose to retain records for a decade to be safe. Electronic invoices must be archived in their original format (typically XML or PDF with embedded XML) to preserve their integrity. The myDATA platform also retains submitted data, but taxpayers are expected to maintain their own compliant archive for the required period. [vatupdate.com]
Format & Storage Requirements: Greek law requires that the integrity and authenticity of e-invoices be ensured during storage. Accepted methods include technical controls (e.g. ensuring the documents contain the AADE-issued unique codes, using internal audit trails, or employing electronic signatures/seals even if not mandatory). Electronic archives can be kept in Greece or abroad, provided that data can be made available to domestic tax authorities on request without delay. Many businesses use cloud storage or entrust archiving to their certified e-invoicing service providers. The archives should store not only the invoice human-readable output but also the structured data file and the metadata (such as the clearance MARK and timestamp). The law does not require paper copies for e-invoices – a printed copy of an e-invoice is not considered a “tax document” on its own unless accompanied by evidence of its clearance (like the QR code/ID).
Readability and Access: Throughout the retention period, invoices must remain readable and accessible for inspection. Tax auditors should be able to verify the contents and the authenticity of invoices. In practice, this means having the ability to reproduce a legible visual representation of the invoice (e.g. a PDF) and providing, if requested, the original XML/JSON data and validation codes. The AADE can cross-check an archived invoice’s MARK against its own records to ensure it matches what was reported. Failure to retain or safeguard the required records constitutes a violation of the Tax Procedure Code (implying possible penalties similar to failing to maintain proper books). Thus, companies must have robust processes for backup and retrieval of e-invoices and ensure that any migration or change in IT systems preserves the documents’ integrity.

9. Penalties & Enforcement

Enforcement Mechanisms: Greek authorities have bolstered the Tax Procedure Code to impose penalties for non-compliance with e-invoicing and e-reporting obligations. Enforcement is two-fold: the AADE’s myDATA system itself prevents or flags non-compliance (e.g., by blocking VAT return filings that don’t match reported data), and financial penalties are levied for failures or inaccuracies. Key provisions include: [vatupdate.com]
  • Failure to Issue an E-Invoice (when required): Under the latest rules, if a taxpayer fails to issue an electronic invoice where it is mandatory (for example, a large company issuing a paper invoice after March 2026), this is treated as if the invoice was not issued at all. The Tax Procedure Code (as amended by Law 5104/2024) applies steep fines in such cases: for VAT-taxable transactions, a penalty of 50% of the amount of VAT that would have been due on the unissued invoice is imposed. If the transaction is non-taxable or exempt (no VAT), a flat fine of €500 per audit for single-entry books, or €1,000 per audit for double-entry (accrual) books is imposed for each unissued (or non-electronically-issued) invoice. These penalties reflect the seriousness of failing to comply with e-invoicing – essentially equating it to not complying with basic invoicing obligations. [vatupdate.com]
  • Failure to Report/Transmit Invoice Data (e-Reporting Violations): Even for transactions not yet subject to mandatory clearance, omitting or delaying the reporting of required data to myDATA is an offense. Earlier regulations (Decision A.1170/2023 under Law 4174/2013) set fines equal to 10% of the transaction’s value for completely unreported invoices, capped at €1,000 per invoice per violation day. Late reporting (after the deadline but before a tax audit) could incur a reduced penalty of 5% of the transaction’s value. Moreover, if an invoice was reported with a lower value than actual (under-reporting) and the buyer corrects it, the supplier faces a penalty of 5% of the undeclared amount. These percentage-based fines were introduced to reinforce timely and accurate e-reporting in the initial phase of myDATA’s enforcement (2022–2023). [vatupdate.com]
  • Other Non-Compliance: Failure to transmit certain required accounting documents (like payroll or stock statements relevant to the e-books) can result in flat fines of €250 (single-entry) or €500 (double-entry) per tax period. Laws also provide for escalation: if repeated violations occur within five years, the fines can double or quadruple. Additionally, the AADE has been actively enforcing point-of-sale reporting: for example, businesses that do not link cash registers to the tax system (to report receipts) have faced severe fines or even suspension of operations. For B2G contracts, while tax law doesn’t specify fines for non-e-invoicing, in practice a supplier’s invoice will not be paid by a public entity unless an e-invoice is properly issued, creating a strong business incentive to comply. Finally, failure to maintain proper archiving of invoices and digital records is punishable under general bookkeeping rules (and could lead to the tax authorities disputing the validity of those invoices). [vatupdate.com] [vatupdate.com]
Greek authorities have signaled that enforcement will intensify: Data analytics on myDATA are used to identify discrepancies, triggering audits if, for instance, a buyer reports an invoice that the seller failed to report. VAT returns that do not align with myDATA records are automatically flagged. As a result, the primary “penalty” for non-compliant taxpayers is often the denial of VAT deductions or delays in VAT refunds until corrections are made. In addition to financial penalties, the tax administration has begun publicly warning non-compliant businesses and even software providers: for example, AADE announced in early 2026 stepped-up inspections and heavy fines for businesses that use non-approved invoicing software or bypass fiscal cash registers. In summary, the enforcement approach combines automated controls (like blocking non-matching returns) with hefty fines and public enforcement actions to ensure high compliance. [vatupdate.com]

10. Pre‑Filled VAT Returns

Introduction of Prefilled Returns: Greece has implemented pre-filled VAT returns (periodic VAT declarations) using the data from the myDATA e-books. The system was piloted in 2022 and rolled out officially from early 2023, with the goal of simplifying compliance and reducing errors. Under the prefill program, the AADE uses all the sales and purchase invoice data that businesses report through myDATA to automatically calculate the amounts for each VAT return field (outputs, inputs, net tax, etc.). The taxpayer can view these provisional figures when preparing the return. Initially, some discrepancy was allowed – for example, in 2024 a 30% deviation between the reported data and the filed return was permitted for both revenue and expense totals. However, the intention is to phase out these tolerances and require that VAT returns exactly match the myDATA figures. In practice, this means that if a business finds the pre-filled numbers are incorrect (perhaps due to a missing invoice or classification error), the business must correct the underlying myDATA reports rather than simply overriding the return. [vatupdate.com]
Current Status: As of 2025, the AADE has tightened the integration between myDATA and VAT filings. The VAT return form on the TAXISnet portal is now largely pre-populated with myDATA data for many fields (e.g., total taxable sales, VAT on sales, deductible VAT on purchases). If a taxpayer attempts to declare less output VAT or more input VAT than what is in myDATA, the system will likely reject the return or prompt for corrections. This effectively makes the pre-filled amounts a minimum floor – taxpayers can declare higher tax due (or lower credits) than the prefilled values, but not the inverse. Only in exceptional cases (like certain allocations or adjustments not captured in myDATA) can differences be justified, and even then supporting documentation may be required. The AADE has reported that the majority of active VAT taxpayers are now filing with fully matched data. [vatupdate.com]
Planned Developments: The move to real-time e-invoicing is expected to further improve the accuracy of prefilled returns. The authorities aim for a future state where VAT returns become almost automatic, with businesses simply confirming the data and paying the resulting amount. Greece is also exploring pre-filled annual income tax returns (Form E3) using myDATA records of revenues and expenses. For now, taxpayers should reconcile their myDATA records with their accounting ledgers before submission deadlines. This includes ensuring any missing invoices are reported or errors corrected (through credit notes or adjusting entries – see Section 13: Summary). The prefilled return initiative is a cornerstone of Greece’s digital tax strategy, heralded as a way to reduce admin burden and improve compliance, and it is being closely watched by other EU countries as a possible model. [vatupdate.com]

11. Impact on SMEs and Startups

Compliance Burden vs. Benefits: Small and medium-sized enterprises (SMEs) in Greece face new compliance requirements under the e-invoicing mandate, but the government has taken steps to mitigate the impact. No size-based exemption (aside from the very small €10k turnover VAT exemption) exists – all SMEs in the VAT system are obligated to use myDATA reporting and, from late 2026, e-invoicing. This means that even startups and micro-businesses need to adapt their invoicing processes. Initially, many SMEs experienced increased administrative workload to integrate new software or to manually report invoices. However, Greece’s Ministry of Finance and AADE have stressed the long-term advantages for businesses: automating tax compliance can reduce human errors, speed up VAT refund processing, and eventually simplify tax filings via prefilled returns. Indeed, companies that embraced myDATA have reported more efficient record-keeping and fewer VAT filing mistakes. There are also potential cash flow improvements, since real-time reporting enables faster detection of issues (like missing invoices) and faster VAT refund verifications. [vatupdate.com], [vatupdate.com] [vatupdate.com] [vatupdate.com]
Support Measures for SMEs: The Greek government and tax authority have instituted several measures to help SMEs and startups transition:
  • Phased Rollout: The mandatory B2B e-invoicing rollout is staggered by business size – large companies first, giving smaller firms an additional 8-month runway (until October 2026) to prepare. This phased approach acknowledges that SMEs may need more time to adjust their systems. [kpmg.com], [kpmg.com]
  • Free Tools: AADE’s free e-invoicing platforms (Timologio and myDATA mobile app) are specifically aimed at SMEs, eliminating the need for costly software for many tiny businesses. These tools allow small businesses to create e-invoices and automatically submit them. AADE has also provided extensive online resources, technical documentation, and a helpdesk (call center 1521 and a dedicated 24/7 online help portal) to support businesses in using myDATA and e-invoicing. [vatupdate.com] [vatupdate.com]
  • Transitional Reporting Options: In the early phase of myDATA, SMEs with very low document volumes could use simplified reporting methods (like manual entry of monthly summary data on the myDATA portal) instead of real-time integration. While real-time reporting is now standard, these measures gave smaller firms breathing room to develop long-term solutions. [vatupdate.com]
  • Financial Incentives: To offset compliance costs, Greece introduced generous tax incentives for early adopters. As detailed in Law 4712/2020 and subsequent amendments, businesses that began exclusively using e-invoicing before it became mandatory receive: (a) super-deduction of 100% of related expenses (software, services, and equipment) in the first year, (b) fast-tracked VAT refunds (within 45 days vs. the usual 90 days) for the periods they use e-invoicing, and (c) a reduced statute of limitations for tax audits (3 years instead of 5) for those years. Furthermore, the 2025 Joint Decision on B2B e-invoicing confirmed that companies implementing e-invoicing at least 2 months before the deadline enjoy 100% enhanced depreciation of e-invoicing investments and a 100% increase in deductible expenses for the first year. These incentives have been particularly welcomed by startups and growing businesses to help cover initial costs. [vatupdate.com], [vatupdate.com] [vatupdate.com] [kpmg.com], [sovos.com]
  • SME Readiness: Studies and public statements suggest that Greek SMEs have been adapting gradually. Many smaller firms rely on accountants or service providers for compliance. Surveys by industry groups and consultancies (Big 4 firms) indicate that, while initial awareness was low in 2021–22, by late 2025 a significant majority of SMEs were aware of the mandate and had plans to comply, often using third-party solutions or the Timologio platform. The AADE’s report that tens of thousands of businesses activated e-invoicing by early 2026 shows that SMEs are moving toward compliance. The government has stated that the e-invoicing project will benefit SMEs by streamlining accounting, reducing the informal economy (creating fairer competition), and hopefully reducing compliance costs in the long run through automation. Potential challenges remain – such as ensuring that the smallest businesses can handle the new requirements and that different e-invoice software solutions are interoperable – but continuous support and gradual implementation are aimed at addressing these issues. [vatupdate.com] [vatupdate.com]

12. Official References

The following are key sources and references related to Greece’s e‑invoicing and e‑reporting regime (all links are up-to-date and publicly accessible):
  • Legislation and Government Releases:
    • Law 4308/2014 – Greek Accounting Standards law (Article 14 establishes rules on invoicing and was amended in 2025 to mandate e-invoicing). [vatupdate.com], [vatupdate.com]
    • Law 4601/2019 – Initial law requiring public-sector bodies to accept e-invoices, aligning with EU Directive 2014/55/EU on B2G e-invoicing. [vatupdate.com], [vatupdate.com]
    • Law 4712/2020 – Introduced voluntary B2B e-invoicing framework and incentives (e.g. tax deductions, audit benefits) for early adopters. [vatupdate.com], [vatupdate.com]
    • Law 4972/2022 – Established the phased B2G e-invoicing mandate (effective 2023–2025) for all government entities and their suppliers. [vatupdate.com]
    • Law 5073/2023 – “Measures to Combat Tax Evasion” law (December 2023) which reinforced myDATA compliance, introduced e-invoicing provisions, and updated penalty rules in the Tax Procedure Code. [vatupdate.com]
    • Law 5144/2024 – New VAT Code (effective Jan 2025) consolidating VAT legislation; includes alignment with EU “Quick Fixes” and SME scheme (Article 44A/44B for small enterprise exemption). [vatupdate.com]
    • Joint Ministerial Decision ΠΟΛ. Α.1138/2020 – Established the myDATA e-books scheme and technical specs for e-reporting.
    • AADE Decision A.1090/2022 – Refined myDATA implementation timelines, requiring near-real-time reporting from 2023. [vatupdate.com]
    • Joint Decision Α.1128/2025 & AADE Decision A.1129/2025 – Key decisions (Sep 2025) detailing the introduction of mandatory B2B e-invoicing from 2026, including scope (B2B domestic and exports) and the phased timeline. [vatupdate.com], [vatupdate.com]
    • Press Release (Feb 17, 2026) – Announcement by the Ministry of Finance and AADE of extended deadlines for large enterprises (Phase 1 of B2B e-invoicing mandate moved to March 2, 2026, with a gradual implementation period to May 3, 2026) and restatement of penalty provisions for non-compliance. (Source: AADE.gr) [vatupdate.com], [vatupdate.com]
  • Technical Guidelines:
    • AADE myDATA Specifications – Official documentation (in Greek) detailing the data schema (Invoice Detail Schema – “InvoiceDoc”) and API for submitting e-books data to the myDATA platform. These are available on the https://www.aade.gr/mydata.
    • Peppol CIUS for Greece – Technical specification for e-invoices to Greek public sector, conforming to EN 16931 standard. Published by AADE’s Interoperability Center (documentation available via https://www.aade.gr/).
  • Tax Authority & Government Portals:
    • AADE – myDATA Information Page: The official AADE webpage on myDATA and e-invoicing, with user guides, FAQ, and announcements.
    • Ministry of Finance Announcements: The Ministry’s press releases (such as the Feb 17, 2026 release) detail policy updates and can be found in Greek on the https://www.minfin.gr and AADE’s site.
    • Taxheaven.gr – Greek Circulars: Repository of Greek tax circulars and decisions, e.g. Circular E.2004/2026 which clarifies e-invoicing obligations and penalties for 2026. [vatupdate.com]
  • Expert Analysis & Newsletters:
    • KPMG TaxNewsFlash (Sept 17, 2025): “Greece: Compliance deadlines for e-invoicing” – overview of the B2B e-invoice mandate and timeline. [kpmg.com]
    • Deloitte Greece Alert (2025): “Mandatory B2B e-Invoicing in Greece” – explanation of the new rules and how businesses can prepare (phased approach from Feb 2026).
    • EY Greece Newsletter (Feb 2024): “Mandatory e-invoicing” – outlines Joint Decision 1128/2025 and 1129/2025 requirements and the state of play as of 2024.
    • Sovos Regulatory Update (Sept 2025): “Deadlines for Mandatory B2B E-Invoicing Announced” – provides an English summary of the phased implementation and early adoption perks. [sovos.com], [sovos.com]
    • Global VAT Compliance (Oct 2025): “Greece Confirms 2026 Rollout of Mandatory E-Invoicing” – details on the AADE’s plans for the myDATA transition and expected impact on businesses.
    • VATupdate.com – Greece section: Ongoing news on Greek e-invoicing and e-reporting developments (e.g. Feb 2026 update on deadline extensions, and various analyses like early 2024 clarifications on small business exemptions, new VAT code, etc.). This site compiles both official news and expert commentary on Greece’s digital tax reforms. [vatupdate.com]
(Each source above is publicly accessible and offers additional details on the Greek e‑invoicing and e‑reporting framework.)

 

13. Summary and Correction Mechanisms

In summary, Greece’s e‑invoicing and e‑reporting system (myDATA) represents a comprehensive real-time VAT control framework covering nearly all transactions of Greek businesses. The mandate’s scope is broad – it includes domestic B2B invoices, retail sales (B2C) data, B2G invoices, and cross-border transactions, ensuring that every sale and purchase is reported to the tax authority. The timeline for mandatory e‑invoicing is phased: large companies by March 2, 2026, and all other businesses by October 1, 2026 (with transitional periods to adapt). Key obligations for taxpayers include issuing invoices in the prescribed format (or via certified platforms), transmitting each invoice’s details to AADE in real-time, and maintaining electronic records and archives of all invoices. Major risks of non-compliance are financial penalties (up to 50% of the undeclared VAT or fixed fines) and the potential loss of VAT deductions if invoice data isn’t properly reported. SMEs need to prepare for the digital transition, but support in the form of free tools, phased implementation, and tax incentives is available to ease their compliance burden. With myDATA, the Greek tax authority is already pre-filling VAT returns and cross-checking all transactions, so businesses must ensure their data is accurate and complete. Critical next steps for businesses are to finalize their e-invoicing solutions ahead of the deadlines, submit the required declarations (by March 2, 2026 for large companies), and train staff on the new processes. Looking beyond 2026, Greece’s experience is likely to inform the upcoming EU-wide digital reporting requirements under the “VAT in the Digital Age” initiative. [vatupdate.com] [vatupdate.com], [vatupdate.com] [vatupdate.com] [vatupdate.com], [vatupdate.com] [sovos.com], [kpmg.com] [vatupdate.com]
14. Correcting E-Invoices and E-Reports:
Under the Greek system, if an **issued e‑invoice contains errors or needs adjustment, the correction is typically made by issuing a corrective document (credit note or debit note) referencing the original invoice. The correction must be reported to myDATA, which will update the digital ledgers. (The invoice issuer should ensure the credit/debit note itself meets all legal requirements and includes a reference to the invoice being corrected.) If an invoice was not transmitted or was reported with wrong data, the general rule is to fix the record in myDATA as soon as possible: for example, by sending the missing invoice data or an amendment. Prior to the VAT return filing, taxpayers can update their myDATA submissions without formal penalties – the corrected data will be used in the prefilled return. However, if an error is discovered after the return is submitted, the business must file an amended VAT return and correct the myDATA entry accordingly (which could trigger interest or penalties if additional VAT is due). Importantly, buyers have a mechanism to “self-report” any supplier invoices not reflected in their myDATA records by the return deadline. By doing so, the buyer ensures the expense and its VAT appear in their e-books (protecting their deduction), and this action flags the issue to the tax authority. The supplier may then be held liable for failing to report the invoice on time. In essence, the onus is on businesses to actively monitor and reconcile their digital records. Greek companies are advised to implement internal controls (e.g. periodic reconciliation of issued and received invoices with myDATA) to catch omissions or discrepancies early. The AADE’s guidance encourages taxpayers to utilize the available correction features in the myDATA platform or their provider’s software to amend any mistakes promptly. This proactive approach, combined with the pre-filled return system, significantly reduces the risk of audits and penalties. By staying vigilant and correcting errors through proper credit notes or adjusted entries in myDATA, businesses can remain compliant and fully benefit from Greece’s digital tax system without interruption.
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Sources:

Laws & Regulations

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