The mandatory e-invoicing framework enters its second implementation phase on October 1, 2026, meaning that businesses falling within this phase must now be prepared for the new invoicing requirements. περνά από την 1 October 2026 στη Β΄ περίοδο εφαρμογής της, με τις επιχειρήσεις που εντάσσονται σε αυτή να πρέπει πλέον να έχουν προετοιμαστεί για το νέο καθεστώς έκδοσης τιμολογίων.
Shortly before the new requirements take effect, the Independent Authority for Public Revenue (AADE) issued additional clarifications regarding an issue that has raised several questions among businesses: the “Declaration of Commencement of Electronic Issuance of Documents”.
Who is ultimately required to submit this declaration? Who is exempt? And why is October 12, 2026 an important date for certain businesses?
Let’s take a closer look at what applies.
Mandatory E-Invoicing: What Applies from October 1, 2026?
From October 1, 2026, mandatory e-invoicing enters into effect for businesses included in the second implementation phase.
In practical terms, simply transmitting invoice data to myDATA is no longer sufficient. Invoices must be issued through the solutions provided for under the mandatory e-invoicing framework.
Businesses can choose between a licensed E-Invoicing Service Provider and AADE’s free timologio / myDATAapp applications.
Similarly, having an ERP or other commercial software system does not automatically mean that a business complies with the new requirement. Businesses must ensure that the solution they use operates in accordance with the applicable requirements.
What Is the Transitional Period Until December 31, 2026?
Businesses included in the second implementation phase have the option of a gradual transition from October 1 through December 31, 2026.
Subject to the applicable conditions, the transitional period allows businesses to temporarily continue issuing invoices using the existing permitted methods, giving them additional time to complete their transition.
However, this does not mean that all businesses can simply wait until the end of December. Specific requirements must be met in order to make use of the transitional period.
For Which Businesses Is October 12, 2026 Important?
According to AADE’s latest clarifications, the deadline concerns businesses included in the second implementation phase with gross revenue of up to €1 million, based on the 2023 tax year, that wish to make use of the transitional period until the end of 2026.
For these businesses, October 12, 2026 is a key date requiring particular attention in relation to the relevant declaration.
Who Must Submit the Declaration of Commencement of Electronic Issuance of Documents?
This declaration concerns businesses that wish to make use of the gradual transition period until December 31, 2026 and, during that period, continue issuing invoices using the existing permitted methods.
The declaration is submitted electronically through myAADE, via the following path:
Applications → Tax Services → myDATA → Declaration of electronic issuance of documents through a Provider, Self-Provider or the timologio application.
Using timologio or myDATAapp? What Has AADE Clarified?
One of the most important points in AADE’s latest clarification concerns businesses that choose to use its free applications.
Businesses using the services of an E-Invoicing Service Provider must follow the procedure applicable to the use of a Provider.
Για τις επιχειρήσεις που χρησιμοποιούν Υπηρεσίες Παρόχου Ηλεκτρονικής Τιμολόγησης, ακολουθείται η διαδικασία που προβλέπεται για τη χρήση Παρόχου.
What Applies to Retail Receipts and B2C Transactions?
Mandatory e-invoicing does not change the way revenue documents are issued for retail transactions with end consumers (B2C).
Therefore, the new requirements do not mean that the process for issuing retail receipts to individual consumers is changing accordingly.
What Should Every Business Check Now?
With the start of the second implementation phase fast approaching, the key priority for every business is to understand exactly what applies to its specific circumstances.
Before October 1, businesses should have determined which e-invoicing solution they will use, whether their existing ERP or invoicing software has been appropriately adapted, whether they intend to make use of the transitional period and, most importantly, whether any declaration or additional action through myAADE is required.
Timely preparation is particularly important, as the required actions are not the same for every business.
Not Sure What Applies to Your Business?
AFS – Athens Financial Services closely monitors developments regarding mandatory e-invoicing and supports businesses in reviewing their obligations and preparing correctly for the transition to the new framework.
If you are unsure whether you need to submit a declaration by October 12, 2026, which e-invoicing solution is appropriate for your business, or what actions need to be completed before the requirements take effect, contact our team.
📞 210 8317 702
📧 info@afs.gr
Alternatively, complete our contact form and the AFS team will get in touch with you to review your business needs.
