Greece B2B E-Invoicing myDATA

Greece Postpones Phase B of B2B E-Invoicing but 1 February 2027 Is the Date to Watch

Greece has moved Phase B of its B2B e-invoicing mandate to 2 November 2026. But the more important deadline comes on 1 February 2027, when direct ERP-to-myDATA transmission will no longer be permitted. Here is what businesses need to prepare for.

8 October 2026

7 min read

On 30 September 2026, one day before it was due to start, AADE postponed the second phase of Greece's B2B e-invoicing mandate. Businesses with gross revenues up to one million euros now begin on 2 November 2026 instead of 1 October.

The delay is not the story. Buried in the same announcement is a date that changes how invoices leave your systems altogether: on 1 February 2027, direct transmission from your own ERP to myDATA stops being permitted.

The revised timeline

2 March 2026 (done)

Phase A

Resident companies with 2023 revenues above one million euros, with a soft launch that ran to early May.

2 November 2026

Phase B begins

Everyone else: businesses with gross revenues up to one million euros. Moved from 1 October.

2 November 2026 to 31 January 2027

Transition period

Businesses may keep issuing through their existing commercial or accounting systems, their ERP, or AADE's special entry form, in parallel with the approved channels.

1 February 2027: the hard one

Approved channels only

Issuance and transmission to myDATA run exclusively through a certified e-invoicing provider or AADE's own applications. The parallel routes close.

What actually changes on 1 February 2027

Greek taxpayers have been reporting to myDATA since 2021, and many of them do it the obvious way: their ERP talks to myDATA directly over the API. That has been a perfectly valid route for five years.

It ends with the transition period. From 1 February 2027, issuing e-invoices and transmitting the data must go through a certified Electronic Data Issuance Provider or one of AADE's free applications, timologio or myDATAapp. The scope named in the announcement is domestic B2B, transactions with non-EU third countries, and B2G.

If your Greek entity sends from its ERP straight to myDATA today, that integration has a shelf life of under four months. Replacing it is not a configuration change. It means choosing a provider, connecting to them, and testing before a hard cut-off. This is the work the postponement actually bought time for, and it is the work most companies will read as "we have until November".

Who has to file a declaration and who does not

AADE clarified this separately in September, and the rule is counter-intuitive enough to get wrong in both directions.

You must file

If you want to use the transition period, that is, to carry on issuing through your existing systems alongside the approved channels between 2 November and 31 January. The declaration takes an effective date of 2 November 2026.

You do not

If you issue exclusively through timologio or myDATAapp from 2 November and do not use the transition period at all. No declaration is required in that case.

The penalties are proportional, which makes them sharp

VATable transactions

An administrative fine of 50% of the VAT amount on the transaction.

Non-VAT transactions

Fixed penalties of EUR 500 or EUR 1,000, depending on the accounting system the taxpayer maintains.

A percentage-of-VAT penalty scales with the invoice. On a large contract that is not a nuisance fine.

The part that matters for German and EU suppliers

This is where Greece differs from France, and where most summaries stop too early.

Domestic Greek B2B

Issuance is mandatory, and acceptance by the receiving business is compulsory.

Sales to businesses outside the EU

In scope of the issuance obligation, and named explicitly in the February 2027 cut-off.

Sales to businesses elsewhere in the EU

E-invoicing remains optional, and the foreign recipient may reject an e-invoice and require another format.

So if you are a German supplier invoicing a Greek customer cross-border, nothing legally compels you. But read the other direction: your Greek customer is rebuilding its finance process around documents that carry a MARK, and from February it cannot receive them through the old routes either. The pressure to send something machine-readable will arrive commercially rather than legally, which in practice is sooner.

If you have a Greek subsidiary, there is no ambiguity. It is in scope as a resident business, and it is the entity whose ERP connection expires in February.

Why the dates keep moving

This is the third postponement in the programme. The original February 2026 start for large businesses moved to 2 March 2026; Phase B moved from October to November 2026. AADE's stated reasoning this time was adoption rather than failure: it cited roughly 488,000 businesses having filed a declaration or taken up a provider or its own applications in the preceding month.

The useful lesson for planning is not "it will slip again". It is that start dates slip and hard cut-offs do not. The November date moved twice. The February date is the one that closes a route, and routes do not reopen.

What to check this month

Find out how your Greek entity transmits today

If the answer is "straight from the ERP", you have a February deadline, not a November one.

Decide whether you need the transition period at all

Using it requires a declaration with an effective date of 2 November. Going straight to an approved channel does not.

Handle the MARK on inbound documents

Invoices from Greek suppliers carry a MARK identifier assigned by myDATA. Your accounts payable process needs to store and reference it, not just the PDF.

Check your archive

Keep the structured original, not the PDF rendering of it.

How we help

As a certified Peppol access point with country-specific connections beyond the Peppol network, we handle Greek requirements alongside your German, French and other European traffic through a single ERP integration, which is exactly the shape of the problem February 2027 creates.

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Sources

AADE: New deadlines for e-invoicing and Phase II of digital transport documents (30 September 2026) AADE: Clarifications on the Declaration of Use for timologio and myDATAapp (22 September 2026) AADE: Mandatory Electronic Invoicing & Digital Goods Movement Documents AADE: myDATA

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