Mandatory B2B e-invoicing in Greece

Until now, a Greek business could issue an invoice from its own accounting or ERP software and simply send a summary of it to myDATA, the tax authority’s e-books platform. Mandatory e-invoicing changes that: the invoice itself must be created electronically through an approved channel and reach both myDATA and the customer in a structured format.

The obligation comes from Articles 14 and 15 of Law 4308/2014 (the Greek Accounting Standards), as amended by Law 5222/2025, and is set out in detail in joint decision Α.1128/2025, later amended by Α.1044/2026 and Α.1198/2026 to move the start dates.

In practice, once the obligation fully applies to you, a B2B invoice written by hand or issued from an ERP without a provider is treated as never issued. That is why it pays to get set up before the transition period ends, not in its last week.

The rollout has two periods, based on gross revenue declared for the tax year that began in 2023:

• First period: businesses with gross revenue above €1,000,000. The original date was 2 February 2026; decision Α.1044/2026 moved it to 2 March 2026, with a phase-in until 3 May 2026.
• Second period: every other business. The original date was 1 October 2026. A joint announcement by the Ministry of Finance and AADE on 30 September 2026 moved it to 2 November 2026, with a transition period from 2 November 2026 to 31 January 2027.

During the transition, businesses may keep using their ERP or AADE’s special registration form alongside e-invoicing, provided the e-invoicing start declaration (Δήλωση Έναρξης Ηλεκτρονικής Έκδοσης Στοιχείων) was filed on time. From 1 February 2027, B2B and B2G invoices must be issued and sent to myDATA only through a provider or the timologio and myDATAapp applications.

Note that accepting e-invoices has been mandatory for everyone since 2 March 2026. Even a small business must already be able to receive invoices from its larger suppliers.

According to AADE’s guidance, an e-invoice is one issued in one of these ways:

• through a certified e-invoicing provider, which applies the authentication code, sends the document to myDATA and delivers it to the recipient,
• through AADE’s free timologio application (desktop),
• through the myDATAapp mobile application.

AADE is explicit that business and accounting software (ERP) is not, on its own, an accepted way to issue invoices for the transactions the obligation covers. ERP software can, however, be used together with a provider, which is usually the practical route when you want customers, products, stock and payments in one system.

You may use a provider and AADE’s apps side by side, for example a provider for day-to-day invoicing and myDATAapp for a one-off invoice away from the office.

The obligation covers domestic business-to-business (B2B) transactions, B2B transactions with businesses in non-EU countries, and invoices to the public sector (B2G), which were already subject to a separate e-invoicing rule for public contracts.

Outside its scope are:

• retail (B2C) transactions, which keep following the rules for fiscal devices or providers,
• intra-EU supplies of goods and services,
• delivery notes, which fall under the separate digital movement documents regime,
• subsidies, grants and accounting entries for which no invoice is issued.

If you issue both retail and wholesale documents, the simplest setup is software that handles both from the same screen, so you never have to remember which document goes through which channel.

E-invoicing providers are companies licensed by AADE. For every invoice they apply a digital mark, transmit it to myDATA, deliver it to the recipient and keep it for as long as the law requires (decision Α.1112/2025). That does not release the business from keeping its own records.

When you work with a provider, an e-invoicing start declaration is filed through myAADE. The provider submits it, and you accept or reject it within 10 days; if you do not respond, it is deemed accepted. This declaration is also what lets you use the transition period. If you issue invoices only through timologio or myDATAapp from 2 November 2026, without using the transition period, no declaration is needed.

If you are not sure your declaration was filed in time, check myAADE and talk to your accountant as soon as possible.

In circular Ε.2004/2026, AADE clarified that once the obligation fully applies, issuing an invoice any other way, for example by hand or only from an ERP without a provider, is treated as failing to issue the document.

Penalties are imposed under paragraphs 5 and 6 of Article 57 of the Tax Procedure Code (Law 5104/2024), case by case. For transactions subject to VAT they are calculated as a percentage of the VAT involved, with minimum amounts that differ for single-entry and double-entry books, and they rise for repeat offences. For transactions without VAT, fixed amounts per audit apply.

During the transition period, using an ERP or the special form alongside e-invoicing is lawful, as long as the start declaration was filed on time. For what this means in your own case, ask your accountant.

eFluper sends your documents directly to myDATA on every plan, and it also connects to the certified e-invoicing provider Impact. With the connection on, the B2B invoices you issue in eFluper go out as e-invoices, with MARK, UID, authentication code and QR code, without changing how you work.

The provider connection is available on every plan and costs from €95 a year (excl. VAT). It covers B2B invoices, invoices to the public sector (B2G) and retail documents (B2C; on the Light plan, service receipts only).

Everything else, customers, products, payments and reports, stays as it is. And because eFluper also pulls from myDATA the documents other businesses issue to you, your suppliers’ e-invoices show up in the same place.