Greece is moving decisively toward mandatory electronic invoicing, and the deadlines are closer than many businesses realise. Whether you supply Greek public sector entities, operate as a large taxpayer, or hold a Greek VAT registration as a foreign business, the obligations under Greece’s e-Invoicing framework are now firmly in scope. This guide sets out what the mandate requires, how the myDATA platform works, what non-compliance costs, and what businesses should be doing right now to prepare.
Greece operates two overlapping e-Invoicing regimes. The first covers B2G transactions, invoices issued to central government entities, and has been in force since 2019. The second, a broader B2B e-Invoicing mandate, is being phased in across the private sector.
For B2G transactions, suppliers are required to issue invoices in a structured electronic format that complies with EN 16931, the European standard for electronic invoicing. EN 16931 defines a semantic data model — in plain terms, it specifies which data fields an e-invoice must contain and how they should be structured so that any compliant system can read and process them without manual intervention. Greece’s B2G implementation runs through both the myDATA and Peppol networks, the pan-European framework used to route e-invoices between businesses and public authorities.
The B2B mandate extends this logic to commercial transactions. Rather than Peppol, it only requires routing through myDATA, Greece’s national digital tax infrastructure. Businesses must generate invoices in a structured format, transmit the relevant data to myDATA, and ensure their counterpart receives notification. For a broader picture of how e-Invoicing requirements for B2B sellers are evolving across Europe, the pattern is consistent: tax authorities want structured, machine-readable data flowing in real time, not periodic paper reconciliations.
Who is responsible for what? The supplier creates the invoice and reports it to myDATA. They then send the invoice in an agreed format to the recipient, as a PDF with QR code or as a structured XML. In practice, compliance falls primarily on the seller, but buyers operating in Greece need compatible systems to receive and process compliant invoices correctly.
My Digital Accounting and Tax Application, myDATA, is operated by AADE, Greece’s tax authority. It functions as the central ledger for all commercial transaction data: every invoice, credit note, and accounting entry must be reported here in real time or near-real time.
The mechanics are straightforward in principle. When a supplier issues an invoice, the key data fields — counterparty identifiers, invoice totals, VAT amounts, and transaction classification — are transmitted to myDATA. The platform validates the submission, logs the entry in the supplier’s digital income book, and simultaneously creates a corresponding entry in the buyer’s digital expense book. This dual-entry logic is the core of the system: AADE has visibility of both sides of every transaction.
For businesses, this changes the compliance equation significantly. Errors in invoice data are no longer caught in an annual audit — they are surfaced in real time. A mismatched VAT rate or incorrect counterparty identifier will either trigger an outright rejection or create a discrepancy that AADE can flag. For more detail on how Greece handles VAT compliance under this framework, see our Greece VAT country guide.
myDATA supports several transmission methods. Businesses can integrate directly via API, use an accredited e-Invoicing service provider, or in some cases upload data through AADE’s online portal. For any business operating at volume, direct API integration or a managed service is the only practical route.
Greece has followed the approach most EU member states are taking: mandate large taxpayers first, then extend to smaller businesses over time. This is sensible in theory — it gives tax authorities the chance to stress-test infrastructure before volume spikes. But it means that the compliance window for businesses further down the scale is shrinking faster than they often realise.
The current phases are as follows:
If your business holds a Greek VAT registration, regardless of where it is established, you are within scope for local sales. It is important to understand when the obligation applies to your business well ahead of time rather than waiting to be penalised — assuming you have more time than you do is a common and costly mistake.
Greece’s penalty framework for myDATA non-compliance is set out under the Code of Tax Procedure (Law 4174/2013) and related ministerial decisions. The penalties are specific, and they compound.
For failure to transmit invoice data to myDATA at all, or transmitting it late, penalties apply on a per-invoice basis. Current guidance indicates fines of 50% of the VAT for taxable transactions, or €500 to €1,000 for exempt transactions for inaccurate or missing submissions. However, for systematic non-compliance or deliberate misreporting, penalties can double or even quadruple, reaching up to €100,000 annually.
For B2G suppliers issuing non-compliant invoices — those that do not meet EN 16931 format requirements or are not transmitted via Peppol — the consequence is more immediate: the invoice will not be accepted for payment. No compliant invoice, no payment. This is not a fine, it is a cash flow event.
Penalties for myDATA and e-Invoicing non-compliance are not theoretical and can be significant. AADE has been actively enforcing, and the combination of per-invoice fines, VAT surcharges, and payment delays for B2G invoices means the cost of getting this wrong is front-loaded, not just an audit risk years down the line.
The Greek government has not left businesses to absorb the cost of e-Invoicing implementation without any support. A package of incentives has been made available, though the specifics have evolved over successive budget cycles, so businesses should verify current entitlements before planning investment decisions.
The headline measures include:
The strategic argument for moving early is straightforward. Businesses that implement ahead of their mandatory deadline have time to run parallel systems, identify data gaps, and train staff without the pressure of a hard compliance date. Those that wait tend to rush implementation, make errors, and face exactly the penalties the system is designed to impose. The incentives make that argument financially as well as operationally.
The end-to-end process is not complicated once the technical integration is in place, but the setup requires careful attention to data quality and format compliance. Here is how it works:
The supplier generates the invoice in their ERP or accounting system. The key data fields — seller and buyer VAT numbers, line items, applicable VAT rates, and transaction classification codes specific to Greece’s myDATA taxonomy — must be correctly populated at source. Errors here flow downstream.
The invoice data is structured into the required format for myDATA transmission. If the business uses an accredited e-Invoicing provider, the provider typically handles format conversion and runs pre-submission validations, checking field completeness, calculation accuracy, and data integrity against myDATA’s schema.
The structured invoice data is submitted to myDATA via API, either directly or usually through a provider. myDATA validates the submission and, if accepted, assigns a unique mark (ΜΑΡΚ), a reference number that confirms the invoice has been logged in the system.
The buyer must be informed of the invoice and, where required, the myDATA mark. For structured B2B e-invoices, this typically occurs through the same transmission channel. For B2G transactions routed via Peppol, the notification flows through the network automatically.
Greece requires that e-invoice data be retained for a minimum of five years. The myDATA platform retains submission records, but businesses should maintain their own audit trail, including the original invoice data, any validation responses, and the myDATA mark, in a format that can be produced on request to AADE.
For businesses using an accredited provider, steps two through four happen largely automatically. The critical work is in step one: getting the source data right.
Start with a scoping exercise: Map every Greek VAT registration your business holds, the volume and type of transactions processed under each, and which myDATA obligations are already active. If you have been reporting to myDATA but not yet issuing fully structured e-invoices, understand the timeline for when that changes.
Audit your current data quality: The most common failure point in myDATA implementation is not the technical integration — it is invoice data that does not meet the format requirements. VAT numbers, transaction classification codes, and exemption reasons all need to be correct at source, before transmission.
Assess your ERP and systems readiness: Most standard ERP configurations were not built with myDATA in mind. Whether you connect directly via API or go through an accredited provider, you will need to understand what your systems can produce today and what gap exists between that and what Greece requires.
Engage a specialist: Greek e-Invoicing compliance sits at the intersection of tax law, technical formats, and operational process. Trying to manage that in-house, without experience in AADE’s specific requirements, is a significant risk. The earlier you bring in support, the more options you have.
Whether you are already live on myDATA and looking to tighten your data quality, or just starting to scope out your obligations, getting the right advice early makes a material difference. Our team works with businesses across Europe on exactly these challenges, from initial impact assessments through to full implementation and ongoing compliance monitoring.
If you have Greek operations and are not yet certain where you stand against the current mandate, now is the right time to find out. Speak to our team today.
1. Does the mandate apply to foreign businesses invoicing Greek customers?
Yes. If you hold a Greek VAT registration, you are within scope. The obligation attaches to the VAT registration, not the country of establishment. A UK or US business with a Greek VAT number must comply with myDATA reporting requirements on the same basis as a Greek-domiciled company. If you supply Greek public sector entities without a VAT registration, the B2G Peppol requirements apply separately. Foreign businesses without any Greek VAT or establishment are generally outside scope, but this should be confirmed against your specific transaction profile.
2. Can a business use its existing ERP system to generate compliant e-invoices?
Possibly, but it depends on the ERP and how it has been configured. The ERP must be capable of producing data in the required structured format and must include Greece’s myDATA-specific classification codes. Many standard ERP configurations do not do this out of the box. Some major ERP vendors have released Greek localisation packages, but the quality and completeness varies. Most businesses find it more practical to connect their ERP to an accredited e-Invoicing provider that handles format conversion and myDATA transmission, rather than attempting to build that capability natively.
3. What happens to invoices issued in PDF format after the mandate takes effect?
If the invoice is not first reported to the myDATA system in the correct, structured format as required, it will not be compliant. A PDF is not a structured electronic invoice — it is a digital image of a document, and myDATA cannot process it as a data submission. Once the mandate applies to your business, invoices must be generated and transmitted in the required structured format. PDFs sent to buyers will not satisfy the e-Invoicing obligation, and failure to transmit the corresponding data to myDATA will trigger penalties. If you are currently operating purely with PDF invoicing, transitioning off it before your compliance deadline should be a priority.
4. How does Greece’s e-Invoicing mandate interact with the pre-filled VAT return system?
myDATA data feeds directly into AADE’s pre-filled VAT return system. Once a business’s invoice data has been transmitted and validated, AADE uses that data to pre-populate the periodic VAT return. The business then reviews, adjusts if necessary, and submits. In principle, this reduces the manual effort involved in VAT reporting — the data is already there. In practice, the pre-filled return is only as accurate as the underlying invoice data, which is why data quality at the point of transmission matters so much. Discrepancies between the pre-filled figures and what a business actually submits will attract scrutiny.
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