Country deep dive
Greece runs one of the tracker's more mature clearance systems: myDATA has required real-time reporting of every invoice since 2021, B2G e-invoicing has been fully mandatory since September 2025, and a domestic B2B mandate is now rolling out in two phases through 2026 — Phase 1 (businesses over €1 million revenue) took effect on 2 March 2026 and is already in force; Phase 2 extends the obligation to every remaining business from 1 October 2026.
AADE's myDATA (My Digital Accounting and Tax Application) platform becomes mandatory for all Greek taxpayers, requiring real-time or near real-time transmission of invoice and bookkeeping data. Every transaction receives a unique registration mark (MARK) and QR code from AADE — the reporting backbone every later e-invoicing layer builds on.
Following a phased rollout across public administrations from September 2023, B2G e-invoicing becomes fully mandatory for all public contracts exceeding €2,500. Suppliers submit EN 16931-compliant invoices (Greek Peppol CIUS) for myDATA validation and MARK assignment, then transmission via accredited Peppol Access Points to the National Interoperability Center (KED).
Structured B2B e-invoicing becomes mandatory for businesses with annual revenue above €1 million, under an EU derogation (Council Implementing Decision (EU) 2025/502) authorising Greece to depart from Articles 218 and 232 of the VAT Directive. Invoices are validated through the myDATA clearance system before exchange. A graduated-enforcement transition period ran through 3 May 2026, during which isolated technical failures did not trigger the full penalty framework.
The domestic B2B e-invoicing mandate extends to every remaining Greek business, with an adjustment period through 31 December 2026. The obligation covers domestic B2B transactions and B2B sales to non-EU entities; intra-EU B2B e-invoicing remains optional for now. Compliance routes include certified e-invoicing providers, AADE's free 'Timologio' app, or direct ERP integration via the myDATA REST API.
Regardless of the domestic mandate's own scope and timeline, the EU's VAT in the Digital Age (ViDA) directive requires structured e-invoicing and digital reporting for cross-border B2B transactions from 1 July 2030 — confirmed EU law (Council Directive (EU) 2025/516).
Two related but distinct standards apply depending on the transaction type: EN 16931 via the Greek Peppol CIUS for B2G, and EN 16931-based invoices validated through the myDATA clearance system for B2B — notably, Peppol is not the mandatory exchange route for B2B, unlike B2G.
The MARK/QR requirement applies uniformly across B2G and B2B — the genuine difference is the transmission channel, not the underlying validation step.
Unlike many peers, Greece offers a genuinely free compliance route (Timologio) alongside certified commercial providers — worth checking before assuming a paid solution is required.
The intra-EU carve-out is a genuine nuance worth noting — a Greek business selling to a German counterpart is not yet mandated to e-invoice that specific transaction, even though its domestic and non-EU sales are.
Every invoice, B2G or B2B, is validated by myDATA and assigned a unique registration mark (MARK) and QR code before it has legal effect — a genuine pre-clearance model, not a post-transaction reporting one. B2G invoices then move on to public bodies via accredited Peppol Access Points; B2B invoices move via certified e-invoicing providers, AADE's free Timologio app, or direct ERP integration through the myDATA REST API.
Greece's reporting-first, invoicing-second sequencing is unusual — most clearance countries built the mandate and the reporting system together, while Greece had years of live myDATA reporting data before layering a full e-invoicing mandate on top.
Phase 1 is already in force as of today — this isn't a future milestone to plan around, it's a current, active obligation for businesses above the revenue threshold.
Businesses should check each counterparty's location carefully — a Greek company's obligations differ meaningfully depending on whether a buyer is domestic, in another EU state, or outside the EU.
With Phase 1 of the domestic B2B mandate already in force and Phase 2 approaching in October 2026, most businesses' near-term work is genuinely time-sensitive rather than exploratory — confirming a compliance route, checking which phase applies, and understanding the mandate's actual scope (domestic and non-EU B2B only; intra-EU B2B remains optional for now).
Phase 1 (revenue over €1 million) is already in force as of 2 March 2026; Phase 2 (all remaining businesses) takes effect 1 October 2026.
A certified commercial e-invoicing provider, AADE's free Timologio app, or direct ERP integration via the myDATA REST API — all are valid, and Timologio is a genuine no-cost option worth evaluating.
The mandate covers domestic B2B and non-EU B2B sales, but not yet intra-EU B2B — confirm which of your transactions are actually in scope before assuming full coverage is required.
Every invoice needs a valid MARK and QR code from myDATA before it has legal effect — this has applied since 2021 and remains foundational to the newer B2B mandate.
Once ViDA's cross-border requirement takes effect on 1 July 2030, intra-EU B2B transactions will need EN 16931 e-invoicing and digital reporting too, regardless of Greece's own domestic scope decisions.
Failure to issue a required e-invoice is treated as non-issuance of the invoice itself — a real, substantial penalty (50% of the VAT that would have resulted), not merely a procedural formality, reflecting the clearance model's underlying purpose of closing the VAT gap.
Other countries in the same region, ordered by their next dated milestone. Each links to a full briefing.