Greece will extend mandatory B2B e-invoicing to all remaining businesses in scope from 1 October 2026. This marks the final major stage in the country’s phased rollout, after larger businesses became subject to the requirement earlier this year.
The Greek e-invoicing mandate has been developing in stages. Greece first moved towards mandatory domestic B2B e-invoicing after receiving EU support for its transition to electronic invoicing and real-time tax reporting. We covered that earlier context in our blog on Greece’s move to mandatory e-invoicing.
The rollout was later formalised into a phased timeline. Large businesses with gross revenue above €1 million, based on their 2023 income tax return, became subject to the requirement from 2 March 2026. The second phase now brings all other businesses covered by the rules into scope from 1 October 2026. For the broader timeline, see our earlier update on the Greece B2B e-invoicing rollout in 2026.
Who is affected from 1 October?
The 1 October deadline applies to remaining businesses covered by the Greek B2B e-invoicing rules. The mandate covers domestic B2B transactions, certain transactions with businesses outside the EU, and business-to-government activity.
Invoices must be issued through an authorised electronic invoicing provider or through the Greek tax authority’s free tools, including timologio and myDATAapp. Transaction data is then transmitted automatically to AADE’s myDATA platform.
Transition period until 31 December 2026
AADE has provided a transition period from 1 October to 31 December 2026. During this period, affected businesses may gradually adopt electronic invoicing while continuing to use other permitted issuance and transmission methods.
This transition period is conditional. Businesses must submit the required declaration on time and state an electronic invoicing start date no later than 1 October 2026.
This follows the same logic as the first implementation phase. Earlier in 2026, Greece moved the first phase go-live for large businesses to March, while keeping the compliance obligation itself in place. That update is covered in our blog on Greece’s Phase 1 e-invoicing go-live.
Why this matters for finance teams
The final wave means Greece is moving from phased implementation to broader operational reality. For finance teams, the impact is not limited to invoice issuance. It also affects ERP integration, master data, invoice validation, tax reporting flows, archiving, and exception handling.
Companies operating in Greece should check whether invoice data can be created, validated, transmitted, and reconciled consistently across their systems. This is especially important for organisations managing multiple invoicing channels, shared service structures, or cross-border operations.
Changes companies need to implement
- Confirm whether local entities are in scope from 1 October 2026.
- Submit the required declaration within the applicable deadline.
- Choose between an authorised provider and the available AADE tools.
- Validate ERP and accounting system readiness for structured invoice issuance.
- Align invoice data with myDATA reporting requirements.
- Set up monitoring for rejected invoices, missing data, and transmission errors.
- Update internal process documentation and responsibilities between finance, tax, and IT.
Key takeaways
- Greece’s final B2B e-invoicing wave starts on 1 October 2026.
- The first wave already applied to businesses with gross revenue above €1 million from 2 March 2026.
- The mandate covers domestic B2B transactions, certain non-EU business transactions, and B2G activity.
- Businesses can use an authorised provider or AADE’s free timologio and myDATAapp tools.
- A transition period runs until 31 December 2026, but only if the required declaration is submitted on time.
