Introduction of  Polish E-invoicing System (“KSeF”), which is coming into effect in Poland on February 1st or April 1st, 2026 will significantly impact

• Polish companies,
• Foreign companies  registered for VAT in Poland,
• Foreign companies with a fixed establishment in Poland.

What is KSeF?

KSeF is a centrally managed IT system through which taxpayers will be obliged to issue and send their invoices to their contractors. It is a game changer, completely altering the current practice, impacting the existing billing and process flows.

KSeF and Swiss entities

Foreign companies registered for VAT in Poland will be required to use KSeF if they have a fixed establishment in Poland. In other cases, they may use KSeF voluntarily.

Nevertheless, the situation is currently being assessed as to whether foreign entities with only VAT registration in Poland, although not required to issue invoices in KSeF, will have to receive invoices via KSeF.

Fixed Establishment

Currently, I strongly recommend that all entities with a registered office outside of Poland, but with VAT registration in Poland, (a) analyze whether they have a fixed establishment, and (b) confirm its absence through an individual interpretation request.

We are already seeing that tax authorities are conducting inquiries in this matter, and it should be expected that, closer to the implementation of KSeF, there will be an expectation to provide explanations regarding the existence of a fixed establishment in Poland or outside of Poland.

Please see suggestion how the project can be tackled