Belgium will introduce mandatory B2B e-invoicing on 1 January 2026, but now The Belgian Tax Administration has announced a three month grace period. This applies only under specific conditions and only to issues directly linked to the new obligation. For background on the reform, see our earlier updates on new guidance for Belgium’s 2026 e-invoicing rules and the B2B e-invoicing decree.
What the grace period means
Companies must show that they took timely and reasonable steps to comply. The measure covers situations where organisations are unable to meet the new requirements despite documented preparation efforts. Examples include missing technical capability to send or receive structured e-invoices or systems and service providers that are not yet ready to issue a valid invoice. Companies still preparing their onboarding can also review our guidance on getting ready for the Belgian B2B mandate.
This is not a postponement of the obligation. The start date of 1 January 2026 remains. Authorities underline that this protects companies that have already invested time and resources in preparing for the reform. The phaseout of the Hermes fallback platform, covered in our update on Belgium closing the Hermes e-invoicing platform, also reinforces the shift toward full structured invoicing.
Why companies cannot delay preparation
The grace period gives limited breathing room for organisations that need a little extra time. It does not remove the obligation to comply. Businesses still need to complete onboarding, validate partner readiness, and ensure that their invoice flows follow EN 16931 standards.
Belgium is one of several European countries moving to structured e-invoicing. Many organisations already use Peppol for invoice exchange. The coming months are therefore crucial for mapping current processes, testing connectivity, and resolving configuration gaps with internal teams or external providers.
What companies should prepare next
The transition period should be used to complete technical implementation and reduce the risk of non compliance after the grace period expires. This includes confirming ERP readiness, testing invoice routing, and validating supplier and customer channels.
Key takeaways
Changes companies need to implement before the deadline include:
- Confirm technical capability to send and receive structured invoices
- Ensure ERP systems and e-invoicing providers can generate valid EN 16931 invoices
- Test Peppol or other approved exchange channels
- Map exceptions and unresolved scenarios that could block invoice processing
- Align internal teams on the new processes for outbound and inbound invoices
