Business-to-business (B2B) e-invoicing will become mandatory in Poland from February 1, 2026. The mandate will apply to resident businesses and businesses with a fixed establishment in Poland with annual revenues exceeding PLN 200 million. It will then extend to most taxpayers on April 1, 2026. Finally, the mandate will extend from January 1, 2027 to the “digitally excluded”. These are taxpayers who find it difficult or impossible to access digital infrastructure — and are therefore unable to fulfil the obligation to issue and receive invoices via KSeF — and whose transactions involve small amounts of up to PLN 450 for a single invoice, and up to PLN 10,000 in total sales per month.

Poland has postponed implementing its e-invoicing mandate numerous times. Following a technical audit, Polish authorities believed that an architecture rebuild was necessary to include better documentation and maintenance planning, as well as training and support for Polish taxpayers.

Businesses will be able to issue and receive e-invoices via the Polish government’s centralised platform for structured e-invoicing, the National Electronic Invoice System, or “Krajowy System e-Faktur” (KSeF), in the FA(3) XML format. 

When an e-invoice is submitted to KSeF, the e-invoice is assigned a unique identifier. Once the e-invoice is approved by KSeF and considered legal, the recipient can download it directly from the platform.

A foreign company operating in Poland through a fixed place of business in the country must issue e-invoices via KSeF and appoint a fiscal representative. A foreign company operating in Poland remotely without a fiscal representative is not obliged to use KSeF. In this instance, the foreign company can issue and receive invoices in the format agreed between both parties, such as PDF via email. 

Poland has announced a grace period for noncompliance penalties. Until the end of 2026, no fines will be imposed on businesses using noncompliant invoices. However, from January 2027, businesses could face fines of up to 100% of the VAT amount on the invoice if they fail to issue an invoice via KSeF. Repeated noncompliance could lead to further administrative penalties and audits.