Portugal was the first country in the world to adopt SAF-T, introducing the standard in 2008. Nearly two decades later, Portugal’s SAF-T (PT) regime continues to evolve, and continues to be delayed. The latest postponement, enacted through the 2026 Budget Bill adopted on November 27, 2025, pushes the first mandatory accounting SAF-T file submission to 2028 for fiscal year 2027 data. Despite the delays, Portugal’s long experience with SAF-T offers valuable lessons for every European country now implementing or expanding similar mandates.
Current status: Monthly billing SAF-T submissions are already mandatory for all VAT-registered businesses. The annual accounting SAF-T file has been postponed to 2028 (for FY 2027). PDF invoices remain accepted until December 31, 2026, after which a Qualified Electronic Signature (QES) becomes mandatory for e-invoices not exchanged via EDI (Electronic Data Interchange).
Two SAF-T Files: Billing and Accounting
Unlike most SAF-T implementations that use a single file format, Portugal’s system is split into two distinct components, each with different submission schedules and requirements:
Billing SAF-T (Monthly)
The billing SAF-T file must be submitted monthly by the 5th day of the month following the transaction period. This requirement applies to both resident and non-resident companies issuing invoices with Portuguese VAT. The file contains invoice data, credit notes, debit notes, and other billing documents. This obligation has been in place since 2013, making it one of Europe’s longest-running periodic SAF-T requirements.
Accounting SAF-T (Annual)
The accounting SAF-T file covers the full general ledger, financial transactions, and account balances for the fiscal year. This more comprehensive file has been repeatedly delayed; originally planned for 2024, it was postponed to 2025, then 2027, and now 2028 (for FY 2027 data). However, businesses must still be able to produce this file on demand during tax inspections.
On-demand requirement: Even though periodic accounting SAF-T submission is not yet mandatory, businesses must produce this file when requested by the Tax Authority (AT) during inspections. Companies should ensure their systems can generate the accounting file at any time to avoid compliance issues during audits.
Timeline of Key Deadlines
- •Monthly (ongoing): Billing SAF-T submission by the 5th of the following month, mandatory for all VAT-registered businesses.
- •Until December 31, 2026: PDF invoices continue to be accepted as valid tax documents without requiring a Qualified Electronic Signature.
- •January 1, 2027: QES becomes mandatory for all electronic invoices not exchanged via EDI (Electronic Data Interchange). Standard PDF documents without QES will no longer be valid.
- •2028: First mandatory annual accounting SAF-T submission, covering FY 2027 data.
- •2030: Target alignment with the EU ViDA framework for digital reporting across the bloc.
A History of Postponements
Portugal’s repeated delays in mandating the accounting SAF-T file illustrate the practical challenges of digital tax implementation, even for a pioneer:
- •2008: Portugal introduces SAF-T (PT), the first country in the world to adopt the OECD standard.
- •2013: Monthly billing SAF-T submission becomes mandatory for all VAT-registered businesses.
- •2024 (planned): Accounting SAF-T file was originally expected to become mandatory. Postponed.
- •2025 (planned): Rescheduled deadline. Postponed again.
- •November 2025: 2026 Budget Bill pushes QES to 2027 and accounting SAF-T to 2028.
Technical Requirements
- •Format: XML following the SAF-T (PT) schema published by the Portuguese Tax Authority (AT).
- •Submission: Electronic filing through the Portal das Finanças.
- •Software certification: Billing software must be certified by the AT. Certified software generates a unique hash chain for invoice integrity verification.
- •Scope: All VAT-registered businesses in Portugal, including non-resident companies issuing invoices with Portuguese VAT.
Lessons for Other Countries
Portugal’s 18 years of SAF-T experience offer several insights for countries now implementing their own mandates, including Bulgaria, Denmark, and others across Europe:
- •Start with billing data. Portugal’s phased approach (billing first, accounting later) allowed businesses to build SAF-T capabilities gradually.
- •Software certification matters. By certifying billing software, Portugal ensures a baseline of data quality across the entire taxpayer population.
- •Delays are common but not free. Every postponement buys time but also delays the tax authority’s ability to use SAF-T data for compliance oversight.
- •On-demand readiness is non-negotiable. Even without periodic filing, businesses must generate SAF-T files for audits. This requirement ensures ongoing system readiness.
Portugal’s pioneering role in SAF-T adoption makes it an essential reference point for the broader European trajectory toward digital tax compliance. As the EU ViDA initiative pushes all member states toward real-time digital reporting by 2030, Portugal’s long journey, with all its lessons and setbacks, provides a realistic picture of what to expect.