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

• Implementation Timeline & Grace Periods:
  • Greece is phasing in mandatory electronic invoicing for B2B transactions starting in 2026. Large enterprises (2023 revenue > €1 million) must begin exclusive e-invoicing by 2 February 2026, with a transition (grace) period until 31 March 2026. During this time, businesses must submit a Declaration of Start of Electronic Issuance or a Declaration of Use of the Timologio App.
  • All other businesses follow from 1 October 2026, with a transition period until 31 December 2026.
  • During these grace periods, businesses are expected to start e-invoicing and file a declaration of commencement (or use of AADE’s Timologio invoicing app) while they adjust; in practice they can run existing invoicing systems in parallel without penalties until full enforcement after the period. (Mandatory e-invoicing for B2G transactions (government contracts) was rolled out earlier – it started 12 September 2023 and covers all public-sector invoices by 1 January 2025.) No general e-invoicing mandate exists yet for B2C, so that remains voluntary in this timeline. [kpmg.com] [edicomgroup.com] [wts.com] [flick.network]
• Transactions in Scope:
  • The e-invoicing mandate applies to domestic B2B sales of goods and services within Greece, as well as B2B transactions between Greek companies and business customers in non-EU countries (exports).
  • Invoices for intra-EU B2B transactions (e.g. a Greek supplier to an EU buyer) are not required to be electronic under this Greek mandate – cross-border EU invoices can still be issued in traditional form if the EU trading partner does not accept e-invoices.
  • Business-to-Government (B2G) invoices are in scope as well (in fact, Greece already mandates e-invoices for public procurement contracts via the Peppol standard).
  • Business-to-Consumer (B2C) transactions are out of mandatory scope – e-invoicing for retail/consumer sales is optional (although retail cash register receipts must still be reported to the tax authority electronically). In summary, from 2026 Greek businesses must issue e-invoices for all domestic B2B sales and for B2B exports outside the EU (while B2C and intra-EU B2B invoicing remain voluntary or subject to future EU-level rules). [ey.com] [edicomgroup.com], [kpmg.com] [wts.com], [edicomgroup.com] [flick.network], [taxathand.com] [kpmg.com]
• Taxable Persons in Scope:
  • The mandate broadly covers all taxable persons established in Greece – i.e. companies, traders, and professionals that keep books under Greek accounting standards (Greek GAAP) and have a Greek VAT registration. This includes domestic businesses of all sizes and sectors (no sector is exempt), as well as Greek VAT-registered entities engaged in activities like imports/exports or public procurement.
  • Non-established (foreign) businesses without a Greek establishment are generally out of scope of Greece’s myDATA e-reporting and e-invoicing obligations. (For instance, a foreign company merely selling into Greece would not use myDATA – instead, the Greek customer’s reporting obligations cover that transaction.)
  • Notably, Greek buyers have to report purchases from suppliers who are not themselves reporting in myDATA (such as foreign or exempt entities) – ensuring transactions involving non-established persons still get recorded.
  • In practice, any Greek-established VAT taxpayer must comply with myDATA reporting, and from 2026 must issue e-invoices for in-scope transactions, or face penalties (no special exclusions by entity type have been announced). [wts.com] [flick.network] [snitechnology.net] [flick.network], [flick.network]
• Data to be Provided (Reporting Content):
  • Companies must transmit a summary of each invoice’s data to the tax authority’s myDATA platform. For every sales invoice (including B2B, B2C, and B2G invoices, as well as credit notes), the issuer is required to send key details electronically – typically the invoice number and date, customer and supplier VAT identification, the net taxable amount, applicable VAT rate and VAT amount, and other relevant invoice elements.
  • Each reported invoice needs to be assigned the appropriate classification (type of sale/purchase, transaction category as defined by IAPR) in the myDATA system. In addition to sales, companies (or in some cases the recipient) must report summaries of expense invoices received (purchases), especially when the issuer is not reporting (e.g. purchases from foreign entities or small suppliers).
  • Apart from invoices, certain accounting records must also be e-reported: this includes documents like payroll records, depreciation/amortization entries, stock and asset adjustments, and other entries needed to determine the taxable results.
  • All these data feed into two electronic ledgers (“e-Books”) maintained on myDATA – an Analytical Book (record of each revenue or expense item with its classification) and a Summary Book (aggregated monthly/yearly totals and results). In short, the mandate requires that all sales invoices issued (and certain key accounting entries, plus unreported purchases) be digitally reported with their essential details and proper categorizations, so the tax authority captures the full picture of each business’s revenues and expenses. [avalara.com], [avalara.com] [snitechnology.net], [snitechnology.net] [snitechnology.net]
• Format of E-Invoices and Reports:
  • Invoices under Greece’s system must be generated in a structured electronic format that can be processed by the tax platform. The format adheres to the European e-invoicing standard EN 16931 – typically an XML schema (or JSON in some cases) containing all the required invoice fields.
  • When an invoice is issued, its data is transmitted to the myDATA platform (either via API or through a certified provider – see transmission methods below). The tax authority’s system validates the data and returns a unique invoice identification code, known as the “MARK” (Μοναδικός Αριθμός Καταχώρισης). This MARK serves as proof that the invoice has been reported; it must appear on the final invoice document (e.g. included in the electronic invoice or as a QR code on a PDF) as a reference.
  • As of 2024, Greece requires that if an invoice is shared in PDF form, it must embed a QR code linking to the myDATA record (the QR is generated using the MARK/URL from myDATA).
  • The e-reporting data (invoice summaries and ledgers) sent to myDATA likewise follow a standardized XML format defined by IAPR, so that the system can automatically update the taxpayer’s electronic books upon receiving each record. All invoice data and their classifications are thus captured in a structured way, enabling automated cross-checks and integration into tax filings. (The Greek e-invoice format itself aligns with EU requirements – for example, B2G invoices use the Peppol UBL format to meet European standard for public procurement – and the same data elements flow into myDATA for tax reporting.) In summary, paper or unstructured invoices are not accepted for in-scope transactions – invoices must be issued electronically in the prescribed format and reported to myDATA, otherwise they are not considered valid for tax purposes. [flick.network] [flick.network], [wts.com] [wts.com] [snitechnology.net] [edicomgroup.com] [flick.network], [flick.network]
• Data Transmission Process & Timing:
  • Taxpayers have several options to transmit invoice data and reports to the authorities, and recent reforms are tightening the timeliness of these transmissions. Businesses can connect their ERP/accounting systems directly to the myDATA platform via API to send invoice data in real time, or they can use an authorized e-invoicing service provider who will handle the data submission on their behalf. For small businesses or those without integrated software, the tax authority provides free tools (the “Timologio” web portal and a mobile app myDATA App) to manually issue e-invoices and automatically transmit them. Retail businesses using certified networked cash registers have their daily receipts data sent automatically through a special system (ESEND) to myDATA as well.
  • In terms of timing, Greece is moving toward continuous transaction reporting – **as of 1 January 2024, any invoice issued via an ERP or other electronic system must be reported to myDATA at the moment of issuance (essentially immediately). This real-time requirement means the invoice’s data is transmitted and validated virtually instantaneously as the sale happens. (To facilitate this, larger companies have integrated systems or use providers to ensure each invoice pings the tax authority for a MARK in real time.) For cases not covered by full automation, the authorities had previously allowed periodic bulk reporting – for example, until recently, companies could transmit all invoice data on a monthly or quarterly basis (with deadlines such as submission by the 20th of the month following the period). However, these lenient periodic deadlines are being phased out.
  • Now, the general rule is prompt or same-day submission of each transaction. If an issuer fails to transmit an invoice’s data on time, the obligation shifts to the recipient, who must report that purchase invoice to myDATA by the deadline of the corresponding VAT return period. (In practice, this means by the end of the next month or quarter when the VAT return is due, the buyer will self-report the invoice if the supplier didn’t.) Additionally, certain industries had specific short timelines during the rollout – e.g. utility companies (electricity, water, telecoms, etc.) using providers were told to transmit within 2 days of invoice issuance during 2023-24. In the event of technical difficulties (system outages), a brief grace is allowed: data can be sent within one day of the original deadline without penalty if, for example, connectivity was lost.
  • Overall, from 2024 onwards Greece’s e-reporting approach effectively functions as a continuous transaction control (CTC) system – aiming for near-real-time upload of each invoice to the myDATA portal, ensuring the tax authority receives sales and purchase information almost immediately. [wts.com], [snitechnology.net] [kpmg.com], [kpmg.com] [taxathand.com] [vatcalc.com]

See also Data on a Greek E-Invoice vs. Data Reported to myDATA (Tax Authority) – Key Differences – VATupdate

• Penalties for Non-Compliance:
  • Strict penalties have been instituted for failing to comply with the myDATA e-reporting requirements (and these will likewise underpin the e-invoicing mandate). Under Law 5073/2023 (recent anti-evasion measures), fines are levied per type of omission. For example, failure to transmit a sales invoice (revenue) to myDATA can result in a fine of 10% of the invoice’s net value, capped at €250 per document per day of delay. Missing the submission of certain records like expense invoices or payroll entries carries a penalty of €250 (for single-entry books) or €500 (for double-entry books) per fiscal year of infraction. If an invoice was not reported by the seller and the buyer’s subsequent “corrective” submission had a higher amount, the seller faces an additional fine of 5% of the invoice’s value for under-reporting. Penalties also apply for not sending transport/delivery notes data (around €100 per omission, capped daily/annually) and other taxable documents. Late submissions (after the deadline but before any audit) incur reduced fines – generally 50% of the above amounts if the data is eventually sent late. Repeat offenders are penalized more heavily: if the same violation is found again within five years, the fine is doubled, and further recurrences can lead to quadruple fines (within certain annual limits). Beyond monetary fines, non-compliance has other consequences: any invoice not properly issued and reported electronically is deemed invalid for VAT purposes, meaning the buyer cannot claim input VAT on it. Businesses that consistently fail to use the e-invoicing system may also face exclusion from public procurement (they could be barred from government contracts or tenders). In short, Greece has backed the e-invoicing/e-reporting mandate with significant enforcement measures – companies should integrate now to avoid fines and the risk of tax disallowances. [taxathand.com] [flick.network], [flick.network]
• Archiving Requirements & Retention Period:
  • Businesses must ensure that electronic invoices are properly archived. Greek regulations require that all invoices (including e-invoices) be stored for at least 6 years for VAT purposes. Electronic invoices, once validated through myDATA, should be kept in a secure digital archive accessible to the tax authorities on request. The archive should preserve the invoice’s integrity and details (including the MARK and any acknowledgment from the authorities) for the full retention period. Notably, once an invoice is in the myDATA system and has a MARK, a paper printout is not legally required – electronic storage suffices. However, taxpayers are expected to maintain their own copy of the e-invoice data (and confirmation receipts) in case of audits, in addition to the data residing on the government’s platform. The retention period of 6 years generally runs from the end of the fiscal year of the transaction, in line with Greek tax record-keeping rules (and this meets the EU minimum, as EU law mandates at least 6 years retention for VAT records). Companies should also follow any specific archiving guidelines from IAPR to ensure the authenticity and legibility of e-invoices over time. In summary, invoices must be archived electronically for six years, and must be available for inspection – the myDATA system records much of the data, but the obligation to keep records remains with the business. [avalara.com], [avalara.com] [flick.network] [avalara.com]
• Pre-Filled VAT Returns:
  • One major goal of Greece’s myDATA e-reporting system is to facilitate pre-population of VAT returns. Since the introduction of myDATA, the Independent Authority for Public Revenue (AADE) can use the transmitted sales and purchase data to draft each taxpayer’s VAT return automatically. In fact, the myDATA platform essentially generates a provisional VAT return based on the total reported outputs and inputs of the business. Currently, this is in a transitional state: taxpayers still review and can amend their VAT returns before submission. They must reconcile the figures with their own accounting records and ensure any discrepancies (for example, an invoice that failed to transmit or was rejected) are corrected either by re-submitting data or adjusting the return. If some invoices were not captured in myDATA by the cut-off, the company can still manually include the values in the VAT declaration – but these situations are becoming more limited as compliance improves.
  • Recent rules (Law 5073/2023) stipulate that the VAT return’s declared revenues cannot be lower than the sum of revenues reported to myDATA, and input claims cannot exceed the purchases reported. This effectively ties the hands of taxpayers to the reported data. The intent going forward is that the VAT return will be fully “locked in” by the e-reported data, removing manual adjustments. The tax authority has indicated that in the near future the pre-filled VAT return will become the final return (no edits allowed), except perhaps within defined correction windows. In other words, once the system is deemed robust, a taxpayer’s VAT liability will be computed directly from the invoices and records in myDATA, streamlining compliance.
  • As of early 2024, taxpayers are advised to align their records with the pre-populated return and fix any issues before filing, because eventually any gap between bookkeeping and myDATA will result in an immediate tax discrepancy. (At the time of writing, Greece does not yet have a completely “final” pre-filled VAT return system like some countries do, but it is providing draft returns and moving toward fully automated VAT declarations.) Importantly, there is no system of pre-filled EU sales listings or other filings mentioned – the focus is on the domestic VAT return. This use of e-invoice data for return prep is a key benefit of the myDATA scheme, potentially reducing compliance effort once everything is fully in sync. [wts.com] [wts.com], [wts.com] [wts.com], [taxathand.com] [vatcalc.com]
• Grace Period Requirements for Greece’s Mandatory E‑Invoicing: Greece is phasing in mandatory B2B electronic invoicing with two groups of taxpayers. Large enterprises (2023 gross revenue > €1 million) must start e‑invoicing from February 2, 2026, and all other businesses from October 1, 2026. Each group has a “grace period” (transition phase) – Feb 2 to Mar 31, 2026 for large companies, and Oct 1 to Dec 31, 2026 for others – to allow a gradual switch-over. During these grace periods, businesses need to take the following steps and meet specific conditions: [taxathand.com], [rsm.global] [kpmg.com], [rsm.global]

  • Submit Required Declarations: By the mandatory start date, every affected business must file a “Declaration of Commencement of Electronic Issuance of Documents” (Δήλωση Έναρξης Ηλεκτρονικής Έκδοσης Στοιχείων) or a “Declaration of Use of the Timologio App” with the tax authority (AADE). This is a one-time registration notifying AADE that the company is beginning e‑invoice issuance, either through an authorized e‑invoicing service provider or via AADE’s free “Timologio” online platform. The declaration must be submitted on time (by Feb 2, 2026 for large firms, or by Oct 1, 2026 for others) and indicate the chosen method of electronic invoicing. (If a company opts for a certified provider, typically the provider can submit this commencement declaration on the company’s behalf via the myAADE portal, but ultimate responsibility lies with the company to ensure it’s done.) Filing one of these declarations by the deadline is a prerequisite for utilizing the grace period arrangements. [kpmg.com], [sovos.com] [anaconda.gr], [aade.gr] [anaconda.gr], [wts.com]
  • Parallel Use of Existing Invoicing Systems: If the required declaration is duly submitted, the business is allowed to continue using its current invoicing system during the grace period while it ramps up the new e‑invoicing method. In other words, from the start date until the end of the transition period, companies can issue invoices both electronically and via their existing processes in parallel. This means you may keep using your ERP/accounting software or even manual invoice issuance (with data reporting to myDATA as presently done) alongside the new e‑invoice system. This dual invoicing allowance is explicitly provided so that businesses can adapt smoothly. However, it only applies “exceptionally” during the grace window and only if the business filed the commencement/use declaration on time. After declaring, you can gradually increase the share of invoices issued as e‑invoices, while phasing out paper or non-electronic invoicing by the end of the grace period. (If the declaration is not submitted by the start date, then the business is technically required to issue only electronic invoices from that date forward, with no transition period relief.) [anaconda.gr], [rsm.global] [taxheaven.gr], [sovos.com] [anaconda.gr], [taxheaven.gr] [anaconda.gr]
  • Technical and Procedural Setup During Grace Period:
  • During the transition months, businesses must initiate their chosen e‑invoicing solution and meet any setup requirements. Each company should decide whether to comply via a certified E‑Invoicing Service Provider or through AADE’s free Timologio web portal / myDATA mobile app. After choosing the solution, the business needs to get the system up and running by the start date: [aade.gr], [rsm.global]
    • If using a certified provider, the company should sign a contract with an authorized e‑invoicing provider and coordinate with them to integrate its billing/ERP system. As part of this onboarding, the “Declaration of Start of Electronic Issuance” must be submitted (usually the provider submits this via the AADE online portal, recording the company’s Tax ID and the provider’s details). The declaration will indicate the date from which the company will begin issuing invoices through that provider (which should be no later than the official start date). The provider’s software must be configured to transmit all invoice data in real time to AADE’s myDATA platform, ensuring authenticity and integrity of each e‑invoice (the provider’s system handles the digital signing/validation as required by law). The business should use the grace period to test and resolve any technical issues with the provider interface so that by the end of the period, 100% of invoices are being issued electronically. [anaconda.gr], [taxheaven.gr]
    • If using AADE’s Timologio application, the business needs to register on the Timologio platform (available via the myAADE/AADE portal) and start issuing invoices through that system. This involves setting up a Timologio account linked to the company’s Tax ID and preparing staff to create invoices using the online interface or the myDATA mobile app. The company must also file the “Declaration of Use of the Timologio Application”, indicating it will use AADE’s free tool from the start date. Once registered, during the grace period the company can begin generating some of its sales invoices in Timologio while still using its old invoicing method for others. It’s important to ensure that all required invoice data (customer VAT, item details, etc.) are input correctly so that the e‑invoices meet the legal specifications. [taxheaven.gr], [aade.gr]
    • Data Reporting: In both cases (provider or Timologio), any invoice issued electronically will be automatically transmitted to the AADE myDATA system as required. During the grace period, for any invoices that you continue to issue in the old way (e.g. through your ERP or manual invoices), you must still report those to myDATA using the usual method (either via your ERP’s myDATA integration or by manually uploading via AADE’s special portal form) just as before. Essentially, during these months you might have two parallel reporting channels: one via e‑invoicing for the invoices you issue electronically, and one via the existing myDATA submission process for any invoices not yet issued through the new system. There are no additional separate reports needed beyond these – the key procedural requirement is simply to start issuing through the new channel and continue submitting everything to AADE (one way or the other) so that no sales go unreported. [taxheaven.gr]
    • No Interruptions: Businesses should use the grace period to train personnel, ensure internal IT systems are compatible, and possibly run dual systems to verify that e‑invoices mirror the information on legacy invoices. It’s advisable to resolve any technical glitches now. Notably, buyers are required to accept electronic invoices from the start of the mandate (for domestic B2B and B2G transactions), so suppliers need not worry about customers rejecting the new format – trading partners in Greece must accommodate e‑invoices by law. All these measures ensure that by April 1, 2026 (for large companies) or January 1, 2027 (for others), the business can fully transition to exclusive e‑invoicing. [taxheaven.gr], [rsm.global]
  • Large Enterprises vs. Other Businesses – Differences in Requirements: Larger companies (revenue above €1M) are simply subject to the new rules about 8 months earlier than smaller firms, but the compliance steps during the grace period are essentially the same for all. The key differences are timing and cut-off dates: [wts.com], [rsm.global]
    • Large enterprises (Phase 1) – Those that exceeded €1,000,000 gross revenue in FY2023 had to begin e‑invoicing by Feb 2, 2026, with their transition period ending Mar 31, 2026. They needed to submit their declarations by that Feb 2 deadline and start adapting in Q1 2026. Many large firms may have more complex ERP integrations, so the grace period was provided for them to adjust systems in early 2026 without penalty. [wts.com]
    • All other businesses (Phase 2) – Companies below the €1M threshold follow the same pattern later in the year: mandatory start by Oct 1, 2026, with a grace period until Dec 31, 2026. They must file the same declarations by Oct 1, and then have Q4 of 2026 to gradually shift to e‑invoicing.
      Aside from these dates, all categories of businesses have to meet the same obligations (choose a compliant e‑invoicing method, file the appropriate declaration, and use the transition period to move to full electronic invoicing). There is no substantive difference in the procedural requirements or the format of e‑invoices between large enterprises and smaller ones under the law – the distinction is solely to phase the rollout. (One minor difference is that early adoption incentives were available: businesses that voluntarily started e‑invoicing two months before their deadline could claim extra tax deductions. For instance, a large enterprise going live by Dec 1, 2025, or a small business by Aug 3, 2026, got 100% enhanced depreciation of related software/hardware and double deduction of e‑invoicing expenses for 12 months. These incentives don’t affect the compliance steps, but they underscore the push for early compliance.) [wts.com] [kpmg.com], [aade.gr] [kpmg.com], [wts.com]
  • Penalty Suspension During Grace Period: Yes, penalties (and strict enforcement) are effectively suspended during the grace period, provided the business meets the conditions. The law stipulates that after the final deadline passes, any invoice not issued through an e‑invoicing system (certified provider or Timologio) will be considered as not issued at all. This would have severe consequences (such invoices would not count for tax purposes, potentially incurring fines for non-compliance and denying the buyer a VAT deduction). During the grace period, however, this rule is relaxed: if you have submitted the required declaration by the start date and are in the process of switching to e‑invoicing, you are explicitly allowed to continue issuing invoices by other means without them being deemed “invalid”. In practice, this means no fines or penalties will be imposed for still using your old invoicing system during the transition months, as long as you are genuinely transitioning (i.e. you filed the declaration and are starting to issue some e-invoices). The authorities have essentially granted a safe-harbor until the grace period ends. It’s important to note that this leniency expires once the grace period is over. After March 31, 2026 (for large companies) or December 31, 2026 (for others), all invoices must be electronic. Any invoice issued by manual or non-electronic means after those dates will legally be treated as not issued (null), which can trigger penalties under the tax procedure code. Moreover, starting immediately from the mandatory dates, buyers are obliged to accept electronic invoices from suppliers, eliminating any excuse for not using the e-invoicing system. The tax authority (AADE) has indicated that enforcement will be strict after the transition: businesses not in compliance could face sanctions, and transactions not properly invoiced electronically will not be recognized. During the grace period, however, compliance enforcement is in a stance of “education and adjustment” rather than punishment – the expectation is that companies use this time to fully comply by the end. (In summary: no penalties for using old invoicing methods during the grace period if the business filed the commencement declaration and is working to implement e-invoicing, but full penalties apply after the grace period for non-compliance.) [taxathand.com] [anaconda.gr], [taxheaven.gr] [taxheaven.gr], [rsm.global]
  • Official Guidance and Documentation: The above requirements are grounded in official Greek legislation and guidance. Joint Ministerial Decision A.1128/2025 (issued 16 Sept 2025) is the key regulation that sets the scope, timelines, and transitional measures for mandatory e‑invoicing. It specifies the phased implementation (Feb 2026 / Oct 2026) and the condition that a Declaration of Commencement or Timologio Use must be filed to utilize the transition period. AADE’s Decision A.1112/2025 (Aug 2025) and related guidelines outline the procedures for e‑invoicing providers and the content/timing of the required declarations. The Greek Independent Authority for Public Revenue (AADE) and the Ministry of National Economy & Finance have also published official announcements and press releases to help taxpayers understand these steps. For example, an AADE press release dated 16 Sept 2025 highlights the deadlines, the need to submit the declarations, and the allowance of “parallel use of ERP or manual invoicing methods during the specified adaptation period”. It also confirms that businesses can choose either certified providers or the Timologio/myDATA app to comply and describes the early adoption incentives. Tax professionals (Big Four firms and local advisors) have issued detailed alerts echoing this official guidance – see KPMG’s TaxNewsFlash, Deloitte’s tax update, and others. Businesses are advised to consult the original Greek decisions (published in the Government Gazette) and AADE’s official FAQ or support lines for e‑invoicing if they need further clarification. In summary, Greek authorities have clearly outlined the “to-do list” for the grace period: register your e‑invoicing method (provider or Timologio) by declaring it, start issuing e‑invoices by that time, and you may temporarily run old and new systems in parallel without penalty – but ensure you fully switch to electronic invoicing by the end of the grace period to avoid compliance issues. All available guidance consistently emphasizes these points, ensuring businesses know how to proceed step by step during the transition to mandatory e‑invoicing. [taxathand.com], [wts.com] [anaconda.gr], [wts.com] [taxheaven.gr], [taxheaven.gr] [aade.gr] [kpmg.com] [taxathand.com] [anaconda.gr], [taxathand.com]
• Role of the myDATA Platform:
  • myDATA (My Digital Accounting and Tax Application) is the central electronic platform underpinning Greece’s e-invoicing and e-reporting reforms. Introduced in 2020 by AADE, myDATA serves as a national digital ledger for businesses: companies must upload all their invoice data and certain accounting records to this platform, which then constitutes their official electronic “books”. The platform receives the data, validates it (for invoices, providing the MARK/unique ID as confirmation), and updates the taxpayer’s electronic records in the form of the Summary and Analytical Books. Through myDATA, the tax authority can monitor all transactions that contribute to a business’s VAT and income tax obligations in near real-time. The system essentially creates a live database of sales, purchases, and other tax-relevant info for each company. This capability is what enables the pre-filling of VAT returns and rapid tax audits – discrepancies between a supplier’s and buyer’s reported data are flagged by the system for follow-up. Notably, the move to mandatory e-invoicing is an extension of the myDATA framework: e-invoicing will channel high-quality, structured data directly into myDATA at the moment of issuance, improving accuracy and timeliness. (Greece obtained EU authorization via Council Implementing Decision (EU) 2025/502 to enforce this real-time e-invoicing system as a special measure through 2027.) The myDATA platform also interfaces with other systems – for B2G invoices, for example, myDATA validates the invoice and then works with the national Peppol access point (KED) to route the invoice to the public entity. In summary, myDATA is the hub: all electronic invoices and tax data flow into it, and it serves as the single source of truth for tax authorities regarding each business’s taxable transactions. Companies must engage with myDATA either directly or via service providers to stay compliant. By centralizing invoice reporting in myDATA, Greece aims to increase tax transparency, reduce VAT fraud (like fake invoice schemes), and simplify compliance through automation. The system is actively evolving, and compliance requirements (like real-time API connections, QR codes, etc.) are regularly updated by AADE to improve the process. All Greek businesses are strongly encouraged to align their processes with myDATA’s requirements ahead of the full B2B e-invoicing mandate in 2026, as this platform is the foundation of both current e-reporting and future e-invoicing in Greece. [wts.com] [snitechnology.net] [eur-lex.europa.eu], [eur-lex.europa.eu] [edicomgroup.com] [edicomgroup.com], [snitechnology.net] [vatcalc.com], [eur-lex.europa.eu] [taxathand.com], [wts.com] [taxathand.com], [vatcalc.com]

• Greek Ministry of Finance & AADE announcements on e-invoicing mandate and timeline; Press release and Joint Decision implementing law 4972/2022 for B2G e-invoicing. [kpmg.com], [kpmg.com] [wts.com]
• KPMG TaxNewsflash – “Greece: Compliance deadlines for e-invoicing” (17 Sep 2025). [kpmg.com], [kpmg.com]
• VATupdate / VATcalc – “Greece B2B e-invoicing February 2026 – myDATA e-reporting” (Dec 2025). [vatcalc.com], [vatcalc.com]
• WTS Global briefing – “Digital Reporting and e-invoicing Requirements in Greece” (12 Feb 2024). [wts.com], [wts.com]
• Deloitte Greece Tax Alert – analysis of Decision A.1170/2023 & Law 5073/2023 (Dec 2023). [taxathand.com], [taxathand.com]
• AADE (IAPR) official myDATA guidance and Greek accounting law references (Law 4308/2014 as amended, etc.) via EY Greece summary. [ey.com]
• Flick Greece e-invoicing guide (Dec 2025). [flick.network], [flick.network]
• EDICOM and SNI Greece myDATA overviews. [edicomgroup.com], [snitechnology.net]
• EU Council Implementing Decision 2025/502 authorizing Greece’s e-invoicing derogation. [eur-lex.europa.eu], [eur-lex.europa.eu]