Greece myDATA in 2026: Real-Time Digital Bookkeeping, Tightened

Greece's myDATA platform — the AADE (Independent Authority for Public Revenue) digital bookkeeping system — has been live since 2020, but 2026 marks the year it has become a near-real-time control mechanism rather than a parallel reporting layer. From early 2026, transmission deadlines have been tightened, mismatch tolerances have been reduced, and a domestic B2B e-invoicing mandate is firmly on the horizon.

What myDATA is

myDATA ("my Digital Accounting and Tax Application") is a continuous transaction control regime: businesses must transmit standardised summaries of every issued invoice and accounting entry to AADE in near-real time. AADE pre-populates VAT and income tax returns based on the data received. Discrepancies between transmitted data and filed returns trigger automated reconciliation.

What changed in 2026

• Transmission window — issuers using a certified e-invoicing provider transmit in near real time (within minutes). Issuers transmitting via accounting software now have a same-day deadline rather than the previous next-day window.
• Reconciliation tolerances — the previously generous tolerance bands between transmitted and declared figures have been reduced; deviations above 1% trigger automatic queries.
• Pre-population — VAT returns are pre-filled from myDATA data; taxpayers can adjust but must explain deviations.

Mandatory B2B e-invoicing — coming

Greece's domestic B2B e-invoicing mandate has been in design since 2024. The Ministry of Finance and AADE have communicated an indicative target of 1 July 2026 for first-wave taxpayers, with full coverage in 2027 — subject to formal legislation. The model under consultation is a hybrid of myDATA (continuous reporting) and a structured e-invoice exchanged via certified e-invoicing providers ("Yphresia Παροχής Ηλεκτρονικής Τιμολόγησης"). The detailed timetable is expected to be published in the second half of 2026.

Until the mandate becomes law, voluntary use of certified e-invoicing providers remains incentivised: faster VAT refunds, reduced tax-audit duration, and a deductibility uplift for set-up costs.

What foreign suppliers should know

If you invoice Greek businesses from outside Greece, you do not transmit to myDATA — your Greek customer is responsible for declaring received invoices to the platform. However, a clean, structured EN 16931 / PEPPOL invoice from you reduces friction on the buyer's side, where data is keyed (or read) into myDATA. As Greece moves to mandatory e-invoicing, expect PEPPOL or AADE-compliant XML to become a standard procurement requirement.

Sources

• Greek Independent Authority for Public Revenue (AADE) — myDATA platform official documentation.
• Joint Ministerial Decision A.1138/2020 establishing myDATA, as amended through 2025.
• Council Implementing Decision (EU) 2024/2402 authorising Greece to require mandatory e-invoicing.