In 2026, electronic invoicing will be mandatory in Portugal for micro, small, and medium-sized enterprises (SMEs). Starting 1st January 2026, it will be necessary to use a qualified electronic signature or a qualified electronic seal on electronic invoices to guarantee their authenticity.

What Changes in 2026:

The requirement applies to SMEs (PME´s): Micro, small, and medium-sized enterprises that supply the public sector are now required to issue electronic invoice documents.

Qualified Electronic Signature:

Starting 1st January 2026, electronic invoices must include a qualified electronic signature or a qualified electronic seal to be considered valid.

What's Already in Effect:

Large Companies: The electronic invoice requirement has been a reality for large companies since January 2021.

Validity of PDF Invoices (until 2025): Until 31st December 2025, PDF invoices, even without an electronic signature, will continue to be accepted as valid documents. However, this situation will change starting in 2026.

This change applies transactions to B to B and B to C transactions and applies to non-residents in Portugal.