Greece's Second E-Invoicing Wave: All Remaining Businesses Join myDATA from 1 October 2026
Greece confirms Phase 2 of its mandatory B2B e-invoicing rollout begins 1 October 2026, bringing every remaining Greek-established business into the myDATA regime after large companies went live in March. A separate e-delivery obligation for goods movements follows on 12 October.
Greece's phased rollout of mandatory B2B e-invoicing reaches its second and final milestone on 1 October 2026, when virtually all remaining Greek-established businesses — those below the €1 million turnover threshold that triggered the first wave — become subject to the myDATA e-invoicing mandate.
Recap: How Greece Got Here
Greece's mandate rests on Law 5222/2025 (July 2025), which amended Article 14 of Law 4308/2014 (the Greek Accounting Standards law) to make structured e-invoicing the legal norm rather than an option. The scope, timing, and technical mechanics were then set out in AADE Joint Decision A.1128/2025, with the European Commission authorising the derogation from standard EU invoicing rules via Council Implementing Decision (EU) 2025/502.
The rollout itself came in two waves:
- 2 March 2026: Large businesses (turnover above €1 million) — roughly 38,000 taxpayers — came into scope, with a soft-launch grace period to 2 May 2026.
- 1 October 2026: All remaining domestically-established businesses join, covering the vast majority of Greek companies and sole traders not already captured in the first wave.
What Changes on 1 October
From this date, second-wave businesses must issue B2B invoices — and B2G invoices and related commercial documents — electronically, transmitting the data to AADE in real time through the myDATA platform, either directly via API, through a certified e-invoicing provider, or using AADE's free Timologio or myDATAapp tools. As with the first wave, an adjustment period runs through 31 December 2026, during which AADE has signalled it will apply the same soft-launch tolerance shown to large businesses in the spring. Invoicing to EU counterparties remains optional for now — only domestic B2B/B2G transactions and non-EU exports are mandatory at this stage.
A Separate, Overlapping Deadline: E-Delivery
Businesses tracking the October dates should not conflate two distinct obligations. Alongside e-invoicing Phase 2, AADE's Ministerial Decision A.1094/2026 (published 29 April 2026) sets a separate timeline for e-delivery — real-time digital reporting of goods movements (dispatch/delivery notes) — under a different legal track:
- Phase B1 of e-delivery becomes mandatory from 12 October 2026
- Phase B2, adding item-level classification data, follows from 1 January 2027
E-delivery applies specifically to businesses that issue delivery notes for goods movements; it does not extend the e-invoicing deadline itself, but the two obligations land within the same fortnight and use overlapping AADE infrastructure, which is a common source of confusion for businesses preparing compliance checklists.
What Businesses Should Do Now
- Confirm whether your business fell outside the March 2026 large-business wave — if so, you are in scope from 1 October 2026
- Choose a compliance route: a certified myDATA e-invoicing provider, AADE's free Timologio/myDATAapp tools, or direct REST API integration
- If you also issue delivery notes for goods movements, check separately whether Phase B1 (12 October) applies to your operations — it is a distinct obligation from e-invoicing
- Use the adjustment period through 31 December 2026 to resolve technical issues, but budget for full enforcement from 1 January 2027
Source
VATupdate, Greece's mandatory B2B e-Invoicing enters its second phase in October 2026; AADE, Joint Decision A.1128/2025 and Ministerial Decision A.1094/2026.
