The Belgian authorities have published on 7 October 2025 a few important updates to its electronic invoicing (e-invoicing) Frequently Asked Questions (FAQ), providing further clarity on the upcoming mandatory e-invoicing regime effective from 1 January 2026.
The deadline of 1 January 2026 remains unchanged, providing Belgian businesses with a limited timeframe to prepare for the implementation of structured electronic invoicing processes. While recent rumours have hinted at the possibility of limited conditional tolerances for companies experiencing practical challenges – with details yet to be clarified – the tax authorities have at the same time clearly stated that there will be no postponement.
The additions in the FAQs provide guidance on the entry into force of the mandate, the risks in case of non-compliance, procedural modalities of the Peppol opt-out, and more. We have summarised the five key updates below:
1. The invoice issue date determines whether the e-invoicing mandate applies
- From 1 January 2026, all invoices within the scope of the mandatory e-invoicing obligation and which are drafted, issued, or sent from that date onwards must be issued as structured electronic invoices, regardless of when the underlying transaction occurred.
- As such, a structured electronic invoice will be required for supplies of goods or services performed in December 2025 but only invoiced in January 2026.
- Credit notes issued in 2026 that amend invoices issued in 2025 must, in principle, be in the same format as the original invoice. If the original invoice was issued in a structured electronic format, the credit note must also be in a structured electronic format. If the original invoice was in PDF format, a credit note in PDF remains acceptable, provided the customer consents. However, in this case, the supplier can also issue the credit note in a structured electronic format without customer consent.
2. Input VAT deduction at risk in case of non-compliance
- The FAQ reiterates that businesses must possess a compliant B2B invoice to exercise the right to deduct VAT on incoming invoices. For transactions subject to the e-invoicing mandate, a structured electronic invoice is required to claim VAT deduction, with limited exceptions under the “substance over form” principle.
- This means that input VAT deduction may be at risk if an unstructured e-invoice is received for transactions within the scope of the mandate.
3. A written mutual agreement is recommended in case of Peppol opt-out
- As of 1 January 2026, structured electronic invoices must, in principle, be issued via Peppol. Deviation from this standard is only allowed if both parties mutually agree and provided the alternative format complies with the European norm related to electronic invoices (EN16931) and its list of syntaxes.
- The FAQ strongly recommends that any mutual agreement on alternative formats or delivery methods be explicit and in writing. Written agreements provide clear evidence in case of inquiries from the tax administration and help prevent unilateral imposition of formats by suppliers.
- Implicit agreements, inferred from conduct such as payment without objection or non-automatic acknowledgements, are more difficult to prove and are discouraged.
- Note that taxable persons still need to possess the technical means to issue and receive structured electronic invoices via Peppol, even when they rely on the opt-out possibility
4. Hermes decommissioned at year-end
- The Hermes e-invoicing solution will be decommissioned on 31 December 2025. After this date, sending or receiving documents via Hermes will no longer be possible.
- Businesses currently using Hermes should coordinate with their Peppol Service Provider or Access Point to ensure a smooth migration to an alternative system. Service providers may contact the Hermes team at FPS BOSA for procedural support.
5. Identifying contracting authorities for B2G e-invoicing
- For transactions in scope of the existing B2G e-invoicing obligations, it will be easier to identify whether a counterparty is considered to be a “Contracting Authority” subject to B2G e-invoicing.
- Businesses can now verify this specific customer status via the Crossroads Bank for Enterprises (CBE). The presence of “Contracting authority” in the “Capacities” section indicates the applicability of the B2G e-invoicing obligation.
The clock is ticking – make sure your business is ready to be compliant
With the transition to mandatory structured e-invoicing approaching fast, the time to act is now. E-invoicing (and e-reporting) are not merely IT integration or finance automation projects, they are strategic compliance initiatives that directly impact tax exposure and operational efficiency.
If you need help understanding the impact of these changes on your business, require an independent expert perspective on your plan to meet this obligation, or are looking for a solution, we are ready to support you with strategic advice and technology (where needed) to help you achieve compliance and operational readiness. Our experienced team is ready to offer trusted insights and guidance, enabling you to navigate the upcoming mandate with confidence and peace of mind.
For more insights, please do not hesitate to reach out to Ellen Cortvriend, Sven Geenens, Brecht Van Petegem, or your regular PwC contact.
