Briefing Document & Podcast: Greece E‑Invoicing & E‑Reporting

1. Introduction & Country Context

1.1. Overview of Greece’s Tax Digitalization Journey

Greece’s path to mandatory e-invoicing has been progressive and layered. The foundation was laid with Law 4308/2014 (Greek GAAP / Greek Accounting Standards), which modernized accounting record-keeping and first addressed electronic invoicing provisions. In 2020, the Independent Authority for Public Revenue (AADE, also referred to as IAPR) launched the myDATA (my Digital Accounting and Tax Application) platform as a voluntary e-reporting system. By November 2021, real-time transmission of accounting data (income and expense documents) to myDATA became mandatory for all Greek businesses. B2G e-invoicing was phased in from September 2023 through a series of waves covering central and non-central contracting authorities, reaching full coverage for all public contracts exceeding €2,500 by September 2025. The culmination is the mandatory B2B e-invoicing mandate, which went live on 2 March 2026 for large enterprises and extends to all remaining businesses from 1 October 2026. [ey.com] [saft-validator.com], [snitechnology.net] [theinvoicinghub.com], [comarch.com] [edicomgroup.com], [vatcalc.com]

1.2. Rationale Behind the Mandate

• VAT gap reduction: Greece historically suffered one of the EU’s largest VAT gaps. The gap fell from €7.5 billion in 2009 to approximately €2.1 billion in 2024, with the government targeting a 9% gap rate. The myDATA platform, POS interconnection, and digital payments are credited with saving up to €7 billion annually in previously lost VAT revenue. [en.parapolitika.gr], [athens-times.com], [vatcalc.com]
• Fraud prevention: The EU Council Decision authorizing the measure explicitly references the objective of detecting non-declaration, under-declaration, and “carousel” fraud more quickly. [eur-lex.europa.eu]
• Administrative modernization: The mandate aims to simplify compliance through pre-filled VAT returns, automated reconciliation, and reduced administrative costs for businesses. [en.parapolitika.gr]
• Alignment with EU/international trends: Greece is aligning with the broader EU ViDA framework and the OECD Continuous Transaction Controls (CTC) model. [integra-in…tional.net]

1.3. Position Within the Regional and International Landscape

Greece is positioned as a moderate mover in the EU context. It was not among the first EU countries to implement mandatory B2B e-invoicing (Italy led from 2019), but it is ahead of many EU peers that have not yet enacted B2B mandates. Greece’s CTC clearance model through myDATA closely mirrors the Italian Sistema di Interscambio approach. However, The Invoicing Hub notes that Greece’s centralized clearance model is not fully aligned with ViDA’s envisioned four- or five-corner network model, meaning adjustments will be required by 2030–2035. [invoicedat…action.com] [theinvoicinghub.com]

1.4. Supranational Authorization / Derogation

• Council Implementing Decision (EU) 2025/502 of 5 March 2025, published in the Official Journal on 13 March 2025, authorized Greece to introduce a special measure derogating from Articles 218 and 232 of the VAT Directive (2006/112/EC). [eur-lex.europa.eu], [eur-lex.europa.eu]
• The derogation applies from 1 July 2025 to 31 December 2027. [eur-lex.europa.eu]
• Greece must submit an evaluation report to the European Commission by 31 March 2027 or request an extension. [integra-in…tional.net]
• The derogation preserves customers’ rights to receive paper invoices for intra-Community transactions. [vatupdate.com]
• The decision will terminate automatically if a general EU-wide electronic invoicing system is adopted by the Council before the end date. [vatupdate.com]

2. Regulatory Framework

2.1. Primary Legislation

• Law 4308/2014 (Greek GAAP — “Ελληνικά Λογιστικά Πρότυπα”), FEK A’ 251/24.11.2014: The core legal framework governing accounting standards, invoicing rules, and electronic invoicing provisions (especially Articles 5, 7, 8–15). [elte.org.gr], [ey.com]
• Law 5222/2025 (“National Customs Code and other provisions – Pension provisions”), FEK A’ 134/28.07.2025: Amends Article 14 of Law 4308/2014 to introduce mandatory B2B e-invoicing and provides for early adoption incentives under new Article 71Θ of the Income Tax Code (Law 4172/2013). [ey.com], [banqup.com], [zeya.com]
• Law 4601/2019: Transposed EU Directive 2014/55/EU into Greek law, establishing the legal basis for B2G e-invoicing. [menocarta.net], [peppol.org]
• Tax Procedure Code (Law 5104/2024, “TPC”): Contains penalty provisions applicable to e-invoicing non-compliance (particularly Article 57, paragraph 13). [ey.com]

2.2. Implementing Regulations, Decrees & Orders

• Joint Decision A.1128/2025 (Deputy Minister of Economy & Finance and AADE Governor): Defines the scope of application, effective dates, methods of e-invoicing, and all implementation details for mandatory B2B e-invoicing. [ey.com], [zeya.com]
• Decision A.1129/2025 (AADE Governor): Specifies the procedure and deadlines for submitting declarations of e-invoicing adoption, and implements the early adoption incentives under Article 71Θ of Law 4172/2013. [ey.com], [zeya.com]
• Decision 163014 EX/2025: Amends invoicing methods for B2G e-invoicing, enabling use of the timologio B2G functionality. [zeya.com]
• Joint Ministerial Decision No. 52445 EX/2023 (FEK 2385B/12.04.2023): Establishes the phased B2G e-invoicing mandate. [ec.europa.eu], [peppol.org]
• AADE Decision A.1138/2020: Operational rules for the myDATA platform. [menocarta.net]
• AADE Decision A.1122/2024 and A.1123/2024: Establish the e-delivery (e-transport) framework, specifying document types, transmission methods, and phased implementation. [pwc.com]
• AADE Decision A.1094/2026: Postpones e-transportation Phase B. [e-invoice.app]
• Joint press release of 17 February 2026: Officially postponed Phase A of B2B e-invoicing from 2 February to 2 March 2026. [marosavat.com], [europe.tho…euters.com]

2.3. Circulars, Official Guidance, Administrative Rulings & FAQs

• Circular E.2030/2025: Clarifies penalties for non-compliance with digital transportation document requirements. [ey.com]
• AADE myDATA API Documentation v1.0.7: Technical specifications for API integration, XSD schemas, and classification code combinations. Available on the AADE myDATA portal. [aade.gr]
• AADE press releases (September 2025, February 2026): Announced implementation timeline, postponement, and enforcement approach. [marosavat.com], [kpmg.com]
• Timologio User Manual and instructional videos: Published by AADE for SMEs adopting the free government tool. [aade.gr]
• No consolidated official FAQ document has been published by AADE specifically for the B2B mandate as of June 2026; guidance is distributed across press releases, decisions, and technical documentation.

2.4. Supranational / International Legal Basis

• EU Council Implementing Decision (EU) 2025/502: Derogation from Articles 218 and 232 of Directive 2006/112/EC (see Section 1.4 above). [eur-lex.europa.eu], [eur-lex.europa.eu]
• Directive 2014/55/EU: B2G e-invoicing directive, transposed into Greek law by Law 4601/2019. [peppol.org]
• Presidential Decree 40/2020 (FEK 85A/15.04.2020) and Law 4961/2022 (FEK 146A/27.07.2022): Appointed the General Secretariat for Information Systems of Public Administration (GSIS PA) as the Greek National Peppol Authority. [peppol.org]
• ViDA Directive 2025/516 (adopted March 2025): Greece’s national system will need to evolve to align with the EU-wide Digital Reporting Requirements (DRR) effective from 1 July 2030 for cross-border B2B, and by 1 January 2035 for domestic alignment. [e-invoice.app]

3. Scope of the Mandate

3.1. Transactions in Scope

• Domestic B2B: Mandatory. All sales of goods and provision of services between entities subject to Greek GAAP within Greek territory must be invoiced electronically through the myDATA platform. Paper and PDF invoices are no longer valid as standalone documents for in-scope transactions; however, the commercial invoice (PDF/paper) may be delivered to the buyer as long as the underlying tax data has been cleared via myDATA and the MARK/QR code is included. [ey.com], [zeya.com]
• Domestic B2G: Mandatory since September 2025 for all public contracts exceeding €2,500. Invoices must be cleared via myDATA and then delivered via the Peppol network to the National Interoperability Center (KED). [theinvoicinghub.com], [ec.europa.eu]
• Domestic B2C: Voluntary for e-invoicing. Retail transactions (B2C) are excluded from the mandatory B2B e-invoicing obligation. However, all B2C transaction data must still be reported to myDATA via electronic tax mechanisms (cash registers). Law 5222/2025 provides that the AADE Governor may issue a decision exempting specific categories from the use of Electronic Tax Machines for retail transactions, allowing them to use timologio or a licensed provider instead. [flick.network], [ec.europa.eu] [ey.com]
• Cross-border B2B (non-EU / third countries): Mandatory. Invoices issued to foreign entities based outside the EU are in scope, with the exception of retail transactions. [ey.com], [zeya.com], [banqup.com]
• Cross-border B2B (Intra-EU): Optional. E-invoicing for sales to EU businesses remains voluntary. If the foreign counterpart refuses the e-invoice, alternative delivery methods may be used. Domestic businesses are not required to accept e-invoices from EU counterparts. [edicomgroup.com], [vatcalc.com], [en.parapolitika.gr]
• Intra-community acquisitions: Invoices received from EU suppliers are not subject to the B2B e-invoicing mandate. However, the Greek buyer must still report these acquisitions to myDATA (as purchase documents from non-Greek issuers). [wts.com], [winsightco…sulting.gr]

3.2. Special Transactions in Scope

• Self-billing: Self-billing is supported within the myDATA framework. The platform supports self-billing document types, and self-billed invoices must be transmitted to myDATA like any other invoice. The e-invoicing obligation also applies to transactions “with persons non-liable to issue an invoice” and to “clearance notes” (self-billing scenarios). [edicomgroup.com] [ey.com]
• Triangulation and chain transactions: No specific exemption or carve-out for triangular transactions has been published by AADE. Invoices issued by domestically established entities as part of multi-party chains are generally in scope if the transaction falls within the categories defined in Article 14 of Law 4308/2014 as amended. For intra-EU triangulation where the Greek entity is the intermediary, the supply may fall under the optional intra-EU category. Detailed AADE guidance on this specific topic has not yet been issued as of June 2026.
• Special VAT regimes: No specific published exemptions exist for margin schemes, travel agents, second-hand goods, flat-rate farmers, or investment gold. However, the AADE’s myDATA classification codes include specific categories for different transaction types, and the general invoicing rules under Greek GAAP continue to apply. Flat-rate farmers on the special scheme may have different reporting obligations, but detailed guidance on their treatment under mandatory e-invoicing has not been separately published.

3.3. Excluded or Exempt Transactions

• B2C retail transactions: Explicitly excluded from mandatory e-invoicing (though myDATA reporting via cash registers is required). [ey.com], [zeya.com]
• Intra-EU B2B transactions: Not mandatory; optional only. [vatcalc.com], [edicomgroup.com]
• Retail transactions with non-EU entities: Excluded from the cross-border B2B mandate. [ey.com], [zeya.com]
• Transactions below the B2G threshold (€2,500): B2G e-invoicing applies only to public contracts exceeding €2,500. [comarch.com]
• Specific exemptions under special provisions: The law states that B2G e-invoicing applies “unless other special provisions are applicable.” No comprehensive list of exempted B2C or simplified invoice scenarios has been published beyond the general exclusion of retail transactions. [ey.com]

4. Taxable Persons in Scope

4.1. Established Domestic Entities

All entities subject to the provisions of Greek GAAP (Law 4308/2014) are in scope. This includes: [ey.com], [zeya.com]

• All VAT-registered Greek companies (corporations, LLCs, partnerships).
• Sole proprietors and freelancers.
• Non-profit entities and public sector entities keeping accounting records under Greek GAAP.
• The mandate applies regardless of sector; all businesses issuing invoices in Greece for qualifying transactions are covered. [invoicedat…action.com]

4.2. Non-Established Entities

• Foreign entities with a fixed establishment in Greece: Subject to Greek GAAP and therefore in scope for transactions carried out from that establishment. [winsightco…sulting.gr]
• Foreign entities registered for VAT in Greece but without a fixed establishment: Generally excluded from the mandate, per the scope defined in EU Council Decision 2025/502, which authorized Greece to impose mandatory e-invoicing for transactions between “taxable persons established in its territory.” [eur-lex.europa.eu], [invoicedat…action.com]
• Foreign entities without domestic VAT registration: Excluded. Non-resident companies not subject to Greek GAAP are out of scope. [snitechnology.net]

4.3. Voluntary Participation

Voluntary adoption of e-invoicing has been available since the launch of myDATA and the certified provider framework. Entities that voluntarily adopted e-invoicing before the mandatory dates can benefit from the early adoption incentives under Law 5222/2025 (see Section 5.2 below). [ey.com], [zeya.com]

4.4. Sector-Specific Rules & Exemptions

No sector-specific exemptions from the B2B e-invoicing mandate have been published as of June 2026. The mandate applies uniformly across all sectors. However:

• Aegean island VAT reduction: Businesses on qualifying Aegean islands apply a 30% reduced VAT rate, which affects the VAT amounts on invoices but does not exempt them from the e-invoicing obligation. [invoicedat…action.com]
• Financial services, healthcare, etc.: No published exemptions. These sectors must comply if they issue invoices under Greek GAAP for in-scope transactions, even if the underlying supply is VAT-exempt.

5. Implementation Timeline

5.1. Legislative History

• November 2014: Law 4308/2014 (Greek GAAP) enacted, establishing the invoicing framework.
• April 2019: Law 4601/2019 transposes EU Directive 2014/55/EU for B2G e-invoicing. [menocarta.net]
• June 2020: AADE Decision A.1138/2020 establishes myDATA operational rules. [menocarta.net]
• October 2020: myDATA voluntary pilot phase begins. [menocarta.net]
• November 2021: Mandatory myDATA e-reporting for all businesses. [saft-validator.com]
• April 2023: Joint Ministerial Decision 52445 EX/2023 for phased B2G e-invoicing. [ec.europa.eu]
• July 2024: Greece submits derogation request to the European Commission. [eur-lex.europa.eu]
• March 2025: Council Implementing Decision (EU) 2025/502 published, authorizing the derogation. [eur-lex.europa.eu]
• July 2025: Law 5222/2025 adopted by Greek Parliament, amending Article 14 of Law 4308/2014 and introducing incentives. [banqup.com], [ey.com]
• September 2025: AADE publishes Decisions A.1128/2025 and A.1129/2025 with implementation details. [ey.com], [zeya.com]
• February 2026: Phase A postponed from 2 February to 2 March 2026. [marosavat.com]

5.2. Voluntary or Pilot Phases

• October 2020 – October 2021: Voluntary myDATA reporting. [menocarta.net]
• Early adoption incentives (Law 5222/2025, Article 71Θ of Law 4172/2013): [ey.com], [integra-in…tional.net]
  • 100% depreciation of software and technical equipment in the year of purchase.
  • 100% increased deductibility of expenses for production, transmission, and archiving of e-invoices for the first 12 months.
  • Condition: Adoption at least two months before the mandatory date (i.e., by 1 December 2025 for Phase A entities, or by 3 August 2026 for Phase B entities). [kpmg.com], [zeya.com]

5.3. Mandatory Go-Live Dates (Phased Rollout)

Phase A — Large Enterprises:

• Effective date: 2 March 2026 (originally 2 February 2026, postponed). [marosavat.com], [edicomgroup.com]
• Taxpayer category: Entities with gross revenues exceeding €1,000,000 in fiscal year 2023. [ey.com]
• Approximately 38,000 businesses are captured. [invoicedat…action.com]
• Gradual implementation period: 2 March – 3 May 2026. [edicomgroup.com], [europe.tho…euters.com]

Phase B — All Remaining Businesses:

• Effective date: 1 October 2026. [edicomgroup.com], [ey.com]
• Taxpayer category: All other entities subject to Greek GAAP.
• Gradual implementation period: 1 October – 31 December 2026. [edicomgroup.com]

Obligation to receive: Acceptance of e-invoices by domestic recipients (B2B or B2G) became mandatory simultaneously with the issuance obligation (from 2 March 2026 for Phase A counterparties). [zeya.com]

5.4. Grace Periods & Transitional Provisions

• Phase A: Transitional period from 2 March to 3 May 2026, during which businesses may continue using ERP/accounting systems in parallel with e-invoicing or use the AADE special registration form. Full penalties apply from 3 May 2026. [marosavat.com], [edicomgroup.com]
• Phase B: Transitional period from 1 October to 31 December 2026. [edicomgroup.com]
• During transitional periods, businesses must submit a Declaration of Commencement of Electronic Issuance of Documents or a Declaration of Use of the timologio application, with an effective start date matching the phase start date. [europe.tho…euters.com], [edicomgroup.com]

5.5. Pre-Mandate Milestones

• myDATA REST API and test environment: Available since the initial myDATA rollout in 2020–2021. API documentation v1.0.7, XSD schemas, and test environments are publicly accessible at aade.gr/myDATA. [aade.gr]
• Timologio v2.0.0: Updated version released with enhanced functionality for movement documents, multilingual invoice issuance, and recipient view features. [aade.gr]
• Certified provider registry: AADE maintains separate lists for B2B and B2G certified providers, with approximately 32 licensed providers currently operating. [integra-in…tional.net], [aade.gr]

5.6. Known or Anticipated Postponements

• Phase A postponement: Originally 2 February 2026, delayed by one month to 2 March 2026 via joint press release of 17 February 2026, citing the need for additional time for technical adjustments. [marosavat.com], [europe.tho…euters.com]
• E-transport Phase B: Postponed from December 2025 to May 2026 (AADE Decision of 29 October 2025), and further postponed by AADE Decision A.1094/2026. [europe.tho…euters.com], [e-invoice.app]
• Phase B (October 2026): No postponement announced as of June 2026. Given the Phase A experience, a delay cannot be entirely excluded but has not been publicly discussed.

6. How E-Invoicing & E-Reporting Really Work — The Operating Model

6.1. Overview of the Operating Model

Greece operates a Centralized Clearance (CTC) model — specifically a Continuous Transaction Controls approach. [invoicedat…action.com], [saft-validator.com]

• Every invoice must be transmitted to the myDATA platform and validated by AADE before it is considered fiscally valid.
• AADE sits between issuance and delivery in the invoice lifecycle: it validates the tax-relevant data and assigns a unique MARK (clearance identifier).
• The role of the tax authority is active and real-time: it validates every invoice, maintains the e-books (electronic accounting records), and uses the data for pre-filled VAT returns and compliance monitoring.
• For B2G, the model adds an additional layer: after myDATA clearance, invoices are delivered via the Peppol network to the National Interoperability Center (KED). [theinvoicinghub.com]

6.2. Step-by-Step Invoice Lifecycle

Step 1 — Invoice Creation: The seller’s ERP, accounting system, or AADE’s free tools (timologio/myDATAapp) generates the invoice data in the required XML format (myDATA proprietary XML schema). [invoicedat…action.com]

Step 2 — Submission: The invoice summary data (not the full commercial invoice) is transmitted to the myDATA platform via one of the permitted channels: direct REST API, certified EDIP (Electronic Data Issuance Provider), timologio, or myDATAapp. [invoicedat…action.com], [theinvoicinghub.com]

Step 3 — Validation: AADE validates the submitted data against schema rules, business rules, and calculation checks. If validation fails, the submission is rejected with error codes, and the issuer must correct and resubmit. [invoicedat…action.com]

Step 4 — Clearance / Acceptance: Upon successful validation, AADE assigns: [invoicedat…action.com], [saft-validator.com]

• A unique MARK (Monadikos Arithmos Katahorisis / Unique Registration Number).
• A verification URL.
• The MARK and QR code (linking to the verification URL) must be included on the invoice before delivery to the buyer.

Step 5 — Delivery to Buyer: The issuer is responsible for delivering the complete invoice (commercial document including the MARK and QR code) to the buyer. The delivery method is not regulated for B2B — the issuer may use email, EDI, PDF, paper, or Peppol. For B2G, delivery must occur via the Peppol network through KED. [theinvoicinghub.com], [invoicedat…action.com]

Step 6 — Retrieval by Buyer: The buyer can verify and retrieve invoices through: [invoicedat…action.com], [aade.gr]

• The myDATA portal (view invoices received).
• QR code scanning for individual verification.
• Direct delivery from the supplier via agreed channels.
• For B2G: status feedback from KED (receipt, acceptance, rejection, payment status). [theinvoicinghub.com]

Step 7 — Archiving: Invoices are stored on the myDATA platform by AADE. AADE retains a copy of the invoice data and the unique identifier (MARK). Taxpayers must also archive invoices in compliance with the retention rules (see Section 13). [menocarta.net]

6.3. Authentication & Access Methods

• myDATA REST API: Authentication via username and subscription key pair. [invoicedat…action.com]
• Timologio/myDATAapp: Authentication via TaxisNet credentials (Greece’s national tax portal login). [aade.gr]
• Third-party authorization: Businesses may authorize certified EDIPs to transmit on their behalf. The certified provider’s unique ID is registered with AADE. [menocarta.net]
• Digital certificates/qualified electronic signatures: Not required per-invoice for myDATA transmission; integrity is guaranteed by the platform’s MARK assignment. [theinvoicinghub.com]

6.4. Offline / Contingency Mode

• Specific offline/contingency procedures for myDATA platform unavailability have not been comprehensively published by AADE. The myDATA e-transport framework includes provisions for “loss of interconnection” scenarios (documented in timologio v2.0.0), but detailed B2B e-invoicing offline procedures are limited. [aade.gr]
• If the platform is temporarily unavailable, businesses would need to issue invoices through alternative means and upload them once connectivity is restored. The specific upload deadline and marking requirements for offline invoices have not been explicitly detailed in published AADE guidance for B2B as of June 2026.

6.5. Buyer-Side Workflow

• Buyers must verify each incoming invoice for a valid MARK, QR code, supplier AFM, classification codes, and VAT calculations. [invoicedat…action.com]
• Buyers must classify received invoices in myDATA using AADE’s classification codes (expense/income categories). [invoicedat…action.com]
• Buyer acceptance is mandatory for domestic B2B transactions — buyers cannot refuse e-invoices from Greek suppliers. [edicomgroup.com], [zeya.com]
• For B2G: the contracting authority sends status feedback (receipt, rejection, dispute, acceptance, payment) back through KED. [theinvoicinghub.com]
• VAT input credit dependency: An invoice without a valid MARK is not fiscally valid, and the buyer cannot claim VAT deduction. [invoicedat…action.com], [flick.network]

6.6. QR Code or Verification Code Requirements

• Mandatory since 1 January 2024 on all PDF invoices issued through myDATA. [invoicedat…action.com]
• The QR code links to the AADE verification page, where any party can confirm whether the invoice has been registered and retrieve its validation status. [invoicedat…action.com], [saft-validator.com]
• The QR code encodes the MARK identifier and the verification URL. [saft-validator.com]

7. Acceptable E-Invoice Formats — Mandatory & Voluntary

7.1. Mandatory Format(s)

• B2B: Invoice tax data must be submitted to myDATA in a proprietary XML format defined by AADE’s technical specifications (XSD schema v1.0.7). This is the structured data that gets validated and receives the MARK. [theinvoicinghub.com], [aade.gr]
• B2G: Invoices must comply with EN 16931 standard and be transmitted via Peppol BIS 3.0 with the Greek CIUS (Core Invoice Usage Specification). [theinvoicinghub.com], [ec.europa.eu], [saft-validator.com]
• Unstructured formats: PDF and paper are no longer sufficient as standalone formats for in-scope B2B transactions. However, the commercial invoice delivered to the buyer may be in PDF or paper form, provided it includes the MARK and QR code and the underlying tax data has been cleared via myDATA. [theinvoicinghub.com]

7.2. Relationship to International / Regional Standards

• EN 16931: Greece’s B2G e-invoicing is fully EN 16931-compliant. The B2B myDATA XML format is a proprietary national schema, not identical to EN 16931 but aligned with its semantic principles. [ec.europa.eu], [flick.network]
• Peppol BIS 3.0: Used for B2G invoice delivery via KED. Greece uses the Peppol BIS Billing CIUS 3.0 with a Greek-specific CIUS adaptation. [ec.europa.eu], [peppol.org]
• EN 16931-1:2026: CEN approved the revised standard in March 2026, updating it for ViDA alignment. Greece will need to adopt this revision as part of its future ViDA compliance. [vatupdate.com]
• National extensions: The Greek CIUS for Peppol includes national-specific fields such as the EAIC (Electronic Invoicing Code) for B2G. [theinvoicinghub.com]

7.3. Voluntary / Legacy / Transitional Formats

• During transitional periods, businesses may continue using ERP/accounting systems in parallel. [edicomgroup.com]
• For intra-EU B2B (optional e-invoicing), any format agreed between parties remains acceptable.
• For B2C, no structured e-invoice format is mandated; standard retail receipt formats via electronic tax mechanisms apply.

7.4. Attachments

• The myDATA platform processes summary tax data, not the full commercial invoice content. Line-item descriptions, payment terms, and commercial details are exchanged directly between buyer and seller. [invoicedat…action.com]
• Attachment handling within the myDATA XML schema is limited. The system focuses on structured tax fields; supplementary documentation (contracts, delivery confirmations) remains outside the platform.
• For B2G via Peppol, attachments may be embedded per the Peppol BIS 3.0 specification (embedded PDF or external references), but the clearance step through myDATA concerns only the structured tax data.

8. Technical & Functional Requirements

8.1. E-Invoice Specifications

Mandatory Data Fields (as transmitted to myDATA): [invoicedat…action.com], [snitechnology.net]

• Issuer AFM (tax identification number) and DOY (tax office).
• Buyer AFM (for B2B/B2G).
• Invoice type code (AADE classification, e.g., 1.1 for standard sales invoice, 5.1 for credit note).
• Invoice number and date of issue.
• Net amounts per VAT rate, VAT amounts, gross totals.
• Revenue/expense classification codes.
• VAT rate category.
• Currency.
• MARK (assigned by AADE upon clearance).
• QR code (mandatory on PDF output since January 2024).

Conditional/Optional Fields:

• Delivery address (for e-transport documents).
• Order references (particularly for B2G, including EAIC).
• Third-party details (for self-billing or clearance notes).
• Discount fields, annotations.

Data Validation Rules:

• Schema validation against XSD v1.0.7.
• Business rule checks (classification code combinations, VAT rate alignment).
• Mathematical consistency checks (net + VAT = gross, line-level totals = header totals).
• Since January 2025, pre-filled VAT returns must match myDATA records with 0% deviation tolerance. [invoicedat…action.com]

8.2. E-Reporting Specifications

• Format: myDATA proprietary XML, structured per AADE’s technical specifications. [snitechnology.net], [aade.gr]
• Mandatory data elements: Summary documents (revenue/expense), classification codes, accounting settlement records (payroll, depreciation, accruals). [snitechnology.net]
• Filing frequency: Real-time or near-real-time for income documents; periodic for expense classifications and accounting settlements. [wts.com], [saft-validator.com]
• Three main document types reported to myDATA: [snitechnology.net]
  • Summary documents (issuer reports all issued documents; recipient reports in specific cases).
  • Classifications (both issuer and recipient classify documents by income/expense type).
  • Accounting settlement records (payroll, depreciation, income/expense adjustments).

8.3. Digital Signature & Integrity Requirements

• No per-invoice digital signature is required for myDATA transmission. Integrity is guaranteed by the platform through the MARK assignment and QR code verification system. [theinvoicinghub.com]
• For B2G via Peppol, the Peppol transport protocol provides integrity assurance.
• Under Greek GAAP Article 15, the authenticity of the origin and integrity of the content of an invoice may be ensured by business controls creating a reliable audit trail, EDI, or advanced electronic signature. [elte.org.gr]

8.4. Real-Time or Near-Real-Time Processing

• The system is designed for real-time clearance: invoices must be transmitted to myDATA and receive a MARK before delivery to the buyer. [invoicedat…action.com], [saft-validator.com]
• Platform performance targets: AADE has not publicly disclosed specific uptime SLAs or response time commitments. The platform occasionally undergoes scheduled maintenance (e.g., timologio/myDATAapp maintenance noted for 9 June 2026). [aade.gr]

9. Correction of Errors in E-Invoices and E-Reporting

9.1. E-Invoice Corrections

• Credit notes and debit notes are supported document types in myDATA (e.g., Type 5.1 for credit notes). They must be issued and transmitted through the platform in the same manner as original invoices. [snitechnology.net], [edicomgroup.com]
• Corrective invoices must reference the original invoice (MARK of the original document).
• Cancellations are supported within the myDATA framework. [edicomgroup.com]
• Corrections must be resubmitted through the platform; informal corrections outside myDATA are not fiscally recognized.
• Specific mandatory content for correcting invoices follows general Greek GAAP requirements (Articles 8–9 of Law 4308/2014): reference to the original invoice, nature of correction, corrected amounts.

9.2. E-Reporting Corrections

• VAT return corrections: AADE uses myDATA data to generate pre-filled VAT returns. Discrepancies between myDATA records and filed returns trigger automatic compliance alerts. Taxpayers can currently modify pre-filled VAT returns, but AADE has announced that in the near future, pre-filled returns will become non-modifiable. [wts.com]
• Amended VAT returns: Available through the standard TaxisNet filing system. [aade.gr]
• Classification corrections: Both issuers and receivers can amend classification codes for previously submitted documents through the myDATA platform.
• Penalties for late/incorrect corrections: Subject to the general penalty framework under the Tax Procedure Code (see Section 14).

10. Transmission & Workflow

10.1. Central Platform

• Platform name: myDATA (my Digital Accounting and Tax Application). [aade.gr], [aade.gr]
• Portal URL: https://mydata.aade.gov.gr/ [mydata.aade.gov.gr]
• Operating authority: AADE (Independent Authority for Public Revenue / IAPR). [aade.gr]
• For B2G delivery: National Interoperability Center (KED) via the Peppol network. [theinvoicinghub.com]

10.2. Transmission Channels

• Direct ERP integration via myDATA REST API: For large enterprises with in-house IT capability. [invoicedat…action.com]
• Certified Electronic Data Issuance Providers (EDIPs): Approximately 32 certified providers operate in Greece. [aade.gr], [integra-in…tional.net]
• Timologio (AADE web application): Free government tool for all businesses, with over 580,000 registered users. [invoicedat…action.com], [aade.gr]
• myDATAapp (AADE mobile application): Free mobile tool for micro-businesses and sole traders. [invoicedat…action.com]
• Electronic tax mechanisms (cash registers): For B2C retail transactions, transmitting via ESEND-compliant registers. [autofact-s…utions.com]
• Special entry form (manual web form): For very low-volume submissions. [snitechnology.net]

10.3. Accredited Service Providers / Certified Intermediaries

• Use of certified EDIPs is permitted but not mandatory — businesses may alternatively use AADE’s free tools or direct API integration. [invoicedat…action.com], [theinvoicinghub.com]
• Certification process: Providers must be licensed by AADE and comply with defined technical and security standards. [integra-in…tional.net]
• Registry: AADE maintains separate certified provider registries for B2B and B2G, accessible on the myDATA portal. [theinvoicinghub.com], [aade.gr]

10.4. Interoperability

• B2G ↔ Peppol: Full interoperability via KED. Greece is a member of the OpenPeppol framework. GSIS PA serves as the Greek National Peppol Authority. [peppol.org], [gsis.gr]
• B2B ↔ Peppol: Not currently mandated for B2B delivery, but Peppol could be used voluntarily for B2B invoice delivery. [theinvoicinghub.com]
• Cross-border interoperability: Limited; the myDATA platform is a national system. Cross-border e-invoice exchange is not currently regulated. [theinvoicinghub.com]

10.5. Deadlines & Timing

• Real-time clearance: Invoices must be transmitted to myDATA and receive a MARK before delivery to the buyer. [invoicedat…action.com]
• General invoicing deadline: Per Greek GAAP Article 11, invoices for goods must be issued at the latest by the 15th day of the month following the supply; for services, by the date the revenue becomes due or the date of receipt of consideration if earlier.
• myDATA reporting deadlines: Real-time for sales documents; classifications and accounting entries follow AADE’s prescribed schedules. [wts.com]
• VAT return filing: Monthly or quarterly, depending on entity size and bookkeeping category.

11. Self-Billing

11.1. Self-billing is permitted under the Greek e-invoicing framework and is explicitly supported within the myDATA platform. [edicomgroup.com], [ey.com]

11.2. Self-billed invoices must be processed through the myDATA platform, receiving a MARK like any other invoice. [edicomgroup.com]

11.3. The authorization process follows general Greek GAAP requirements (prior agreement between parties). The mandatory e-invoicing obligation explicitly covers transactions “with persons non-liable to issue an invoice” and “clearance notes.” [ey.com]

11.4. Mandatory content rules follow the standard invoice content requirements under Articles 8–9 of Law 4308/2014, with the addition that self-billed documents must carry appropriate myDATA document type codes.

11.5. myDATA includes specific document type codes for self-billing scenarios within its classification system. [autofact-s…utions.com]

11.6. No specific published restrictions for foreign buyers without a domestic tax number in the context of self-billing have been identified. The general exclusion of non-established entities from the mandate applies.

11.7. Detailed AADE guidance on buyer-side validation or approval requirements specific to self-billed invoices within the B2B e-invoicing mandate has not been separately published as of June 2026.

12. Triangulation & Special Scenarios

12.1. Triangulation Transactions

• No specific published AADE guidance addresses the treatment of triangular transactions under the B2B e-invoicing mandate as of June 2026.
• General principle: if the Greek entity issues an invoice for a domestic B2B supply or a supply to a non-EU entity, it falls within the mandatory scope. If the invoice is for an intra-EU supply (e.g., the intermediary invoices an EU buyer), it falls under the optional intra-EU category.
• myDATA classification codes include specific categories for different supply types that would accommodate triangulation reporting.

12.2. Chain Transactions

• No specific chain transaction documentation requirements beyond general Greek GAAP invoicing rules and myDATA reporting have been published.
• The e-transport (e-delivery) framework, when fully operational, will provide additional documentation for the physical movement of goods in chain transactions. [pwc.com]

12.3. Cross-Border Reverse Charge

• Outbound invoices: Greek businesses issuing invoices with reverse-charge notation to EU counterparts are not required to use the mandatory e-invoicing system (intra-EU transactions are optional). [edicomgroup.com]
• Inbound reverse-charge invoices: Greek buyers receiving reverse-charge invoices from EU suppliers must report these as purchase documents to myDATA (buyer-side reporting obligation for intra-community acquisitions and services received from non-established suppliers). [wts.com], [winsightco…sulting.gr]

12.4. Zero-Rated and Exempt Supplies

• Zero-rated exports (non-EU): In scope — invoices to non-EU entities are mandatory. [ey.com]
• Intra-community supplies: Optional for e-invoicing; however, must still be reported to myDATA as income documents.
• Exempt supplies: Must be reported to myDATA using appropriate classification codes. The myDATA classification system includes specific codes for exempt transactions. [invoicedat…action.com]

12.5. Local Nuances & Special Cases

• Aegean island reduced VAT rates: 30% reduction applies to certain Aegean islands, affecting VAT calculations on invoices. [invoicedat…action.com]
• E-transport (digital delivery notes): A parallel obligation under AADE Decisions A.1122/2024 and A.1123/2024, requiring real-time transmission of goods movement documents to myDATA. Phase A (issuance and transmission) mandatory since December 2025; Phase B (recipient monitoring, quality/quantity control) being phased in during 2026. [pwc.com], [e-invoice.app]
• Construction reverse charge, VAT groups, fiscal representatives: No specific published guidance on their treatment under the e-invoicing mandate beyond general Greek VAT law.

13. Archiving & Retention

13.1. Central Archiving by the Platform

• AADE retains a copy of all invoice data and unique identifiers (MARK) submitted to the myDATA platform. [menocarta.net], [aade.gr]
• Central storage does not fully relieve taxpayers of their own archiving obligations; taxpayers must maintain their own records in compliance with Greek GAAP. [theinvoicinghub.com]

13.2. Mandatory Archiving Format

• Structured electronic invoices must be stored electronically in accordance with AADE regulations. [menocarta.net]
• The original XML data submitted to myDATA constitutes the primary archival record. PDF renditions may be maintained for commercial purposes.

13.3. Retention Period

• B2G invoices: Must be archived for 6 years. [theinvoicinghub.com]
• General VAT/accounting records: Under Greek GAAP (Law 4308/2014, Article 7), accounting records must be retained for a minimum of 5 years from the end of the fiscal year to which they relate. However, in practice, the statute of limitations for tax audits can extend retention requirements to 5–10 years depending on circumstances. [menocarta.net], [elte.org.gr]

13.4. Storage Location Requirements

• Greek GAAP Article 7 permits storage of accounting records in Greece or in another EU/EEA country, provided they are accessible to the tax authorities upon request.
• Third-country storage may require prior notification or authorization. Specific published guidance on offshore storage for e-invoices under the new mandate has not been separately issued.

13.5. Integrity, Authenticity & Readability

• Must be guaranteed throughout the retention period. [menocarta.net]
• The MARK and QR code system provides an integrity verification mechanism throughout the document’s lifecycle.
• Access to documents in a readable format and ability to download them for tax audits must be ensured. [menocarta.net]

13.6. Audit Accessibility

• AADE has real-time access to all data stored on the myDATA platform. [aade.gr], [taxation-c….europa.eu]
• Taxpayers must be able to provide archived invoices to tax authorities upon request.
• The myDATA portal allows both businesses and AADE to view complete transaction histories. [gov.gr]

14. Penalties & Enforcement

14.1. Grace Period / Transitional Enforcement

• Phase A: Transitional period 2 March – 3 May 2026 with graduated enforcement. Full penalties apply from 3 May 2026. [marosavat.com], [invoicedat…action.com]
• Phase B: Transitional period 1 October – 31 December 2026. Full penalties apply from 1 January 2027. [edicomgroup.com]

14.2. Penalties for Non-Compliance

Failure to issue an electronic invoice is treated as non-issuance of the invoice, triggering penalties under the Tax Procedure Code: [marosavat.com], [vatcalc.com], [theinvoicinghub.com]

• VATable transactions: Administrative fine of 50% of the VAT amount that would have resulted from the unissued invoice. [vatcalc.com], [marosavat.com]
• Non-VATable transactions: [vatcalc.com], [europe.tho…euters.com]
  • €500 per tax audit for entities keeping single-entry books.
  • €1,000 per tax audit for entities keeping double-entry books.
• Digital transportation documents (e-transport): Penalties for transporting goods without required digital documents are tenfold: €5,000 per tax audit for single-entry books; €10,000 per tax audit for double-entry books. In case of repeat offenses, the penalty doubles. [ey.com]
• Loss of VAT input credit: An invoice without a valid MARK is not fiscally valid, and the buyer loses the right to deduct VAT. [invoicedat…action.com], [flick.network]

14.3. Penalty Amounts & Calculation Methods

• Penalties are differentiated by whether the transaction is VATable (percentage-based: 50% of VAT) or non-VATable (fixed amounts: €500 or €1,000). [vatcalc.com]
• No specific published escalation mechanisms for repeat e-invoicing offenders beyond the general tax procedure rules. The e-transport regime includes explicit doubling of penalties for repeat offenses. [ey.com]

14.4. Article References & Official Sources

• Tax Procedure Code (Law 5104/2024), Article 57, paragraph 13: Penalties for non-issuance of invoices. [ey.com]
• Joint Decision A.1128/2025: Enforcement framework for mandatory e-invoicing. [ey.com]
• AADE press release of 17 February 2026: Clarification of penalty regime and postponement. [marosavat.com], [europe.tho…euters.com]

15. Pre-Filled VAT Returns

15.1. Greece currently offers pre-filled periodic VAT returns based on myDATA data. [saft-validator.com], [autofact-s…utions.com], [wts.com]

15.2. Details of Pre-Filling

• AADE uses myDATA data to generate pre-filled VAT returns covering both income (sales) and expense (purchase) data. [saft-validator.com], [vatcalc.com]
• Since January 2025, pre-filled VAT returns require 0% deviation tolerance — meaning the VAT return data must match myDATA records exactly. [invoicedat…action.com]
• Taxpayers can currently modify the pre-filled returns, but AADE has announced plans to make them non-modifiable in the near future. [wts.com]
• Discrepancies between myDATA-reported data and filed returns trigger automatic compliance alerts. [autofact-s…utions.com]

15.3. The pre-filled VAT return system is already operational and continues to be refined.

15.4. The dependency on e-invoicing/e-reporting data is direct and critical: the pre-filled returns are generated entirely from myDATA submissions. [saft-validator.com], [vatcalc.com]

15.5. Greece’s pre-filled VAT return approach is aligned with the ViDA vision of automated VAT reporting based on digital transaction data. The country is among the EU leaders in implementing this concept. [vatcalc.com]

16. Readiness for VAT in the Digital Age (ViDA)

16.1. Country Position Relative to ViDA

• Greece is ahead of the ViDA timeline in terms of domestic B2B e-invoicing and real-time reporting, having implemented both before the ViDA deadlines. [e-invoice.app]
• ViDA key dates for reference: [e-invoice.app]
  • 1 July 2030: Cross-border B2B DRR (Digital Reporting Requirements) for intra-EU transactions.
  • 1 January 2035: Domestic alignment deadline.
• Greece’s domestic mandate (2026) is well ahead of the 2035 domestic deadline.

16.2. Alignment of the National System with ViDA Requirements

• Gaps identified: [theinvoicinghub.com]
  • Greece’s centralized clearance model (CTC) is not fully aligned with ViDA’s envisioned four- or five-corner network model. Major adjustments will be needed by 2030–2035 to transition toward standardized interoperable network models.
  • The B2B myDATA XML format is a proprietary national schema, not directly EN 16931-compliant (though B2G is EN 16931/Peppol-compliant). [theinvoicinghub.com], [ec.europa.eu]
  • The newly approved EN 16931-1:2026 standard (ViDA-aligned) will need to be adopted. [vatupdate.com]
• Strengths: Real-time reporting, pre-filled VAT returns, and the MARK/QR verification system provide a strong foundation for ViDA compliance.

16.3. Cross-Border Digital Reporting

• Greece’s myDATA platform is currently a domestic system with no direct feed into a supranational VAT information exchange system.
• From 1 July 2030, Greece will need to ensure that cross-border B2B transaction data feeds into the EU-wide DRR system. This will require platform evolution and interoperability with the EU-wide framework. [e-invoice.app]

16.4. Implications for Businesses

• Businesses complying with the Greek mandate are building infrastructure that provides a strong foundation for future ViDA obligations (real-time data transmission, structured invoicing, classification systems). [invoicedat…action.com]
• Additional adjustments may be needed for EN 16931-1:2026 compliance, Peppol-based B2B exchange, and cross-border DRR connectivity.
• Early adopters benefit from tax incentives (100% depreciation and deductibility) and operational experience that will ease the ViDA transition. [ey.com], [integra-in…tional.net]

17. Impact on SMEs and Startups

17.1. Phased Onboarding

• Phase A (March 2026): Only large enterprises (>€1M revenue in 2023). [edicomgroup.com]
• Phase B (October 2026): All remaining businesses, including SMEs, micro-enterprises, and sole traders. [edicomgroup.com]

17.2. Government Support & Free Tools

• Timologio: Free web application by AADE for invoice creation and transmission, with over 580,000 registered users. Supports B2B and B2G invoicing. [aade.gr], [invoicedat…action.com]
• myDATAapp: Free mobile application for sole traders and micro-businesses. [invoicedat…action.com]
• Special entry form: Free web-based manual form for very low-volume submissions. [snitechnology.net]
• Test environment: Available for businesses and providers to test integrations before going live. [aade.gr]
• Instructional videos and user manuals: Published by AADE on the timologio and myDATA pages. [aade.gr], [aade.gr]

17.3. Simplified Regimes & Threshold-Based Exemptions

• No threshold-based exemption from the B2B mandate exists — all businesses subject to Greek GAAP are covered once their phase becomes effective. [ey.com]
• The free government tools (timologio, myDATAapp) serve as the simplified compliance path for smaller taxpayers, removing the cost barrier. [invoicedat…action.com]

17.4. Subsidies or Financial Support Programs

• Early adoption tax incentives (Law 5222/2025): [ey.com], [zeya.com], [kpmg.com]
  • 100% depreciation of software and equipment costs in the year of purchase.
  • 100% increased deductibility of e-invoicing-related expenses for 12 months.
  • Condition: Adoption at least 2 months before the mandatory date.
• No separate government grants or subsidies beyond the tax incentives have been announced.

17.5. Compliance Costs

• One-time costs: For businesses using free AADE tools, one-time costs are minimal (internet access, basic training). For businesses integrating ERP systems or using certified providers, costs include API development, software upgrades, and employee training.
• Ongoing costs: Certified provider fees (subscription or per-invoice); ERP maintenance; classification and reconciliation effort. The free AADE tools eliminate ongoing platform access costs for smaller businesses. [invoicedat…action.com]

17.6. Cash Flow & Operational Benefits

• Faster VAT refunds: Improved compliance profile and real-time data availability support faster processing. [vatcalc.com]
• Reduced administrative burden: Automated data transmission eliminates manual filing of Customer-Supplier Lists. [aade.gr]
• Pre-filled VAT returns: Reduce manual data entry and error risk. [saft-validator.com]
• Earlier error detection: Real-time validation catches errors at the point of issuance. [invoicedat…action.com]

17.7. Administrative Burden vs. Simplification

• Initial burden: Significant for businesses without existing digital infrastructure — need to adopt new tools, train staff, and adjust workflows.
• Long-term simplification: Once operational, the system automates reporting, reduces reconciliation effort, and eliminates paper-based processes.
• The provision of free government tools is explicitly designed to minimize the cost burden on SMEs. [en.parapolitika.gr]

17.8. Market Impact

• Increased digitalization creates opportunities for early adopters and technology providers.
• The certified provider market (approximately 32 providers) is competitive and growing. [aade.gr]
• Interoperability challenges remain for cross-border operations.

17.9. Official Assessments of SME Readiness

• The European Commission’s“Mind the Gap” country fiche for Greece recognizes the widespread use of digital tools (myDATA, POS, e-Appodixi) as best practices, while noting that the large number of tax expenditures and the absence of a formal compliance strategy remain areas for improvement. [taxation-c….europa.eu]
• The Phase A postponement (February to March 2026) was explicitly motivated by the need to give businesses additional time for technical adjustments. [marosavat.com]

18. Official References & Sources

18.1. Government Portals

• myDATA platform: https://mydata.aade.gov.gr/ [mydata.aade.gov.gr]
• AADE (IAPR) website: https://www.aade.gr/en/iapr [aade.gr]
• AADE myDATA e-books portal: https://www.aade.gr/en/mydata [aade.gr]
• Timologio application: https://www.aade.gr/en/timologio [aade.gr]
• Gov.gr — myDATA access: https://www.gov.gr/en/org/aade/phorologia-epikheireseon/elektronika-biblia-epikheireseon-mydata [gov.gr]
• Gov.gr — Timologio service: https://www.gov.gr/en/upourgeia/upourgeio-oikonomikon/oikonomikon/timologio [gov.gr]
• GSIS — Peppol information: https://www.gsis.gr/polites-epiheiriseis/pliromes-kai-eispraxeis/e-invoice/peppol [gsis.gr]

18.2. Legislative Texts

• Council Implementing Decision (EU) 2025/502: https://eur-lex.europa.eu/eli/dec_impl/2025/502/oj/eng [eur-lex.europa.eu]
• Law 4308/2014 (Greek GAAP): https://elte.org.gr/wp-content/uploads/2021/03/Law_4308_2014.pdf (unofficial English translation) [elte.org.gr]
• Law 5222/2025: Published in Government Gazette FEK A’ 134/28.07.2025. [banqup.com]

18.3. Technical Specifications

• myDATA API Documentation v1.0.7: Available at https://www.aade.gr/en/mydata [aade.gr]
• Classification codes: COMBINATIONS_OF_CLASSIFICATIONS_v1.0.6.xlsx (downloadable from AADE). [aade.gr]
• XSD schemas: Version v1.0.7 (downloadable from AADE). [aade.gr]
• OpenPeppol Greece profile: https://peppol.org/learn-more/country-profiles/greece/ [peppol.org]

18.4. Tax Authority Publications

• EY Greece Tax Alert — Mandatory e-invoicing: https://www.ey.com/en_gr/technical/tax/tax-alerts/mandatory-e-invoicing [ey.com]
• EY Greece Tax Alert — Digital tax environment (August 2025): https://www.ey.com/content/dam/ey-unified-site/ey-com/en-gr/technical/tax/tax-alerts/2025/08/alert-recent-developments-in-the-digital-tax-environment-en.pdf [ey.com]

18.5. Advisory Firm Newsletters & Analysis

• Deloitte Greece: https://www.deloitte.com/gr/en/services/tax/perspectives/mandatory-b2b-e-invoicing-in-greece.html [deloitte.com]
• KPMG: https://kpmg.com/us/en/taxnewsflash/news/2025/09/greece-compliance-deadlines-electronic-invoicing.html [kpmg.com]
• PwC Greece: https://www.pwc.com/gr/en/tax-flashes/2024/Tax_Flash_Legal_framework_on_E-delivery_Eng.pdf [pwc.com]
• Zepos & Yannopoulos: https://www.zeya.com/newsletters/b2b-e-invoicing-becomes-mandatory-greece-2026-what-you-need-know [zeya.com]
• WTS Global: https://wts.com/global/publishing-article/20240212-greece-digital-reporting-and-e-invoicing~publishing-article [wts.com]
• EDICOM: https://edicomgroup.com/blog/greece-mandatory-electronic-invoice [edicomgroup.com]
• Comarch: https://www.comarch.com/trade-and-services/data-management/e-invoicing/e-invoicing-in-greece/ [comarch.com]
• Marosa VAT: https://marosavat.com/vat-news/greece-to-mandate-b2b-e-invoicing [marosavat.com]
• The Invoicing Hub: https://www.theinvoicinghub.com/einvoicing-compliance-greece/ [theinvoicinghub.com]
• VATCalc: https://www.vatcalc.com/greece/greece-mydata-e-book-and-e-invoices-update/ [vatcalc.com]
• VATupdate.com: https://www.vatupdate.com/2025/03/14/proposal-for-authorising-greece-to-implement-mandatory-electronic-invoicing-for-b2b-transactions/ [vatupdate.com]
• Integra International: https://integra-international.net/vida/eu/greece/ [integra-in…tional.net]
• Thomson Reuters: https://europe.thomsonreuters.com/uk/compliance/regulatory-updates/greece [europe.tho…euters.com]
• European Commission eInvoicing Hub: https://ec.europa.eu/digital-building-blocks/sites/spaces/DIGITAL/pages/467108887/eInvoicing+in+Greece [ec.europa.eu]

18.6. Link Status

All links above were verified as accessible during the research for this analysis (June 2026). The European Commission’s eInvoicing country sheet for Greece still lists B2B as “NO” (with a note that legislation is expected), reflecting a lag in updating the EU portal relative to the actual go-live. [ec.europa.eu]

19. Summary & Key Takeaways

19.1. Scope

• Covered: Domestic B2B, B2B with non-EU entities (excluding retail), B2G (>€2,500). All entities subject to Greek GAAP.
• Excluded: B2C retail, intra-EU B2B (optional), foreign entities not established in Greece.

19.2. Format

• B2B: Proprietary myDATA XML for clearance; commercial invoice delivery format unregulated (PDF/paper permitted with MARK + QR code).
• B2G: EN 16931 / Peppol BIS 3.0 with Greek CIUS.
• Legacy formats: No longer valid as standalone for in-scope B2B transactions.

19.3. Timeline

• 2 March 2026: Phase A mandatory (>€1M revenue, 2023). Grace period until 3 May 2026.
• 1 October 2026: Phase B mandatory (all other businesses). Grace period until 31 December 2026.
• EU derogation valid: 1 July 2025 – 31 December 2027. Evaluation report due by 31 March 2027.

19.4. How It Works

• Centralized CTC clearance model via myDATA.
• Invoice data submitted → AADE validates → MARK + QR code assigned → Issuer delivers to buyer.
• Four compliance channels: ERP API, certified EDIP, timologio (free), myDATAapp (free).

19.5. Key Obligations

• Issuers: Must transmit tax data to myDATA in real-time and include MARK/QR on invoices.
• Receivers: Must verify MARK, classify received invoices, and reconcile with myDATA records. Acceptance of e-invoices is mandatory.
• Reporting: All income/expense data to myDATA; pre-filled VAT returns with 0% deviation tolerance.
• Archiving: Minimum 5–6 years; electronic storage with integrity, authenticity, and readability guarantees.

19.6. Main Risks

• Non-compliance penalty: 50% of VAT for VATable transactions; €500/€1,000 for non-VAT transactions.
• Loss of VAT input credit: Invoices without valid MARK are fiscally invalid — direct financial exposure for buyers.
• Supplier dependency: Buyer’s VAT deduction depends on supplier’s proper transmission to myDATA.
• Operational disruption: Mixed-format invoice processing during transitional periods.

19.7. SME Implications

• Free tools available: Timologio and myDATAapp eliminate cost barriers.
• Phased approach: SMEs have until October 2026, with a grace period through December 2026.
• Early adoption incentives: 100% depreciation + 100% deductibility for proactive adopters.
• Challenge: Operational adjustment, classification learning curve, and reconciliation processes.

19.8. ViDA / International Readiness

• Greece is ahead of the ViDA domestic timeline (2035) but faces alignment challenges with the ViDA network model (clearance vs. four-corner).
• B2G already EN 16931/Peppol-compliant; B2B uses proprietary format.
• Cross-border DRR connectivity (by 2030) will require platform evolution.
• EN 16931-1:2026 adoption will be needed.

19.9. Critical Dates & Next Steps

• NOW (June 2026): Phase A businesses must be fully operational; penalties in force since 3 May 2026.
• 3 August 2026: Deadline for Phase B businesses to adopt early and qualify for incentives.
• 1 October 2026: Phase B mandatory go-live.
• 31 December 2026: End of Phase B transitional period; full enforcement begins 1 January 2027.
• 31 March 2027: Greece must submit evaluation report to the European Commission or request extension of the derogation.
• 1 July 2030: ViDA cross-border B2B DRR effective — Greece must ensure interoperability.
• 1 January 2035: ViDA domestic alignment deadline.