Starting 1 January 2026, structured electronic invoicing (e-invoicing) becomes mandatory for all B2B transactions in Belgium. Over half a million companies are already connected to Peppol, and adoption continues to accelerate. But for organisations still completing their integrations, the Belgian Tax Administration (FOD Financiën / SPF Finances) has introduced an important mechanism: a conditional 3-month grace period.
This measure does not delay the mandate. The deadline remains firm. But it does offer businesses breathing room after the first detected non-compliance, provided they can demonstrate genuine efforts to comply.
Below is a clear breakdown of how this grace period works, when it applies, and what companies must do to qualify.
Belgium’s Royal Decree on B2B e-invoicing defines a system of administrative fines for companies that fail to:
send or receive structured electronic invoices,
use Peppol BIS 3.0 (UBL 2.1) as the required standard,
maintain the technical capability to process incoming e-invoices.
To ensure fair enforcement, especially for SMEs still finalising their technical setup, authorities introduced a safeguard: the second (and any subsequent) infraction may only be established at least three months after the previous one.
This rule has been widely interpreted — including by PwC, Deloitte Legal, and VAT-Consult Belgium — as a de facto 3-month grace period.
The grace period is not a blanket waiver and not a transition phase.
It is a mandatory delay between penalties, giving companies a realistic opportunity to fix their systems.
A company is audited or flagged as non-compliant.
Common examples include:
no ability to send/receive Peppol invoices,
ERP not yet generating valid UBL files,
integration with the provider still in progress.
The first violation can result in a fine (up to €1,500).
From that moment, the 3-month period begins.
During this time, tax authorities will not apply a second fine.
The company must prove “timely and reasonable steps” to comply, such as:
contractual agreements with an e-invoicing provider,
active Peppol onboarding,
ongoing implementation or testing,
clear evidence of project progress.
Only after 3 months may another violation be established and fined if the company still isn’t compliant.
This protects companies from repeated penalties while still enforcing the mandate.
The Belgian grace period is often misunderstood. It does not:
postpone the mandate,
allow invoices to be sent as PDF after 1 January 2026,
provide immunity from the first fine,
apply to general VAT obligations.
Belgium is explicit:
Companies that prepared on time must not be penalised by a global postponement.
The grace period primarily helps:
SMEs still integrating Peppol capabilities,
companies dependent on external providers,
groups rolling out multi-entity ERP changes,
organisations replacing outdated invoicing processes.
These firms get a realistic window to fix issues after their first violation, without facing immediate cumulative penalties.
Belgium’s administrative fines for non-compliance with the new B2B e-invoicing rules:
€1,500 — first infraction
€3,000 — second infraction (but only after 3 months)
€5,000 — third and subsequent infractions
Thanks to the mandatory 3-month interval, companies have time to resolve technical issues before exposure to higher fines.
To ensure the grace period works in your favour:
Keep evidence of contracts, emails, integrations, and project milestones.
Choose a certified Access Point or solution provider.
Check support for Peppol BIS 3.0 / UBL 2.1.
Belgium remains committed to a hard go-live on 1 January 2026 for mandatory B2B e-invoicing. The newly acknowledged 3-month grace period is not a postponement but a fair enforcement buffer for companies that act proactively.
Businesses that can demonstrate clear progress will avoid repeated penalties — but the expectation is clear: every company must be technically ready to send and receive structured e-invoices in 2026.