Poland KSeF – 2026 grace period?

However, a pressing question remains for businesses: What happens if taxpayers don’t use KSeF in 2026? Will there be penalties? No! Will it affect my customers’ ability to deduct VAT? Yes!

Recent guidance from the Polish Ministry of Finance offers some clarity—but also points to potential risks that go beyond formal sanctions.

Read in our Polish VAT guide more about compliance obligations.

No penalties until 2027—but that’s not the full story

The Ministry of Finance has confirmed that there will be no financial penalties or formal sanctions for non-compliance with the KSeF e-invoicing obligation until 1 January 2027. This transitional period throughout 2026 is designed to give businesses time to adjust to the system and iron out any implementation challenges.

So, technically, taxpayers who continue issuing invoices outside KSeF in 2026 will not be fined. This may lead some businesses to assume they can postpone implementation without consequence.

But that interpretation would be short-sighted. The absence of formal penalties does not mean that issuing invoices outside of KSeF in 2026 is without risk—especially when it comes to VAT compliance and income tax documentation.

Risks to VAT deduction for customers

One of the central purposes of KSeF is to create a secure, standardized framework for issuing and tracking invoices. In doing so, it provides both suppliers and buyers with a reliable digital audit trail—one that supports the exercise of due diligence, a critical concept in Polish VAT law.

The Ministry has made it clear that KSeF will significantly simplify the process of proving that a taxpayer acted with due diligence when deducting input VAT. This matters because, under Polish tax rules, a buyer must be able to show that they took reasonable steps to ensure that a transaction was genuine and that the supplier was properly registered for VAT.

So what happens if a seller issues an invoice outside KSeF during the grace period in 2026? Formally, the buyer can still deduct VAT from such an invoice. The Ministry has not indicated that non-KSeF invoices during 2026 will automatically disqualify input VAT.

However, such invoices will not benefit from the protective digital infrastructure of KSeF. As a result, buyers may face a higher evidentiary burden if they are audited. They could be asked to provide additional documentation, explain the transaction in greater detail, or even face delays in VAT refunds. In this sense, non-KSeF invoices may be perfectly legal—but they are inherently less robust in a compliance setting.

This creates a reputational and practical risk for businesses that delay KSeF implementation. If a company continues to issue traditional invoices in 2026, its customers may begin to question whether those invoices offer the same level of security and legal protection as those issued through KSeF.

Why timely adoption still makes sense

Even though there is a grace period until 2027, the benefits of early KSeF adoption are clear. By issuing invoices through the system starting in February or April 2026, businesses can provide their customers with a more secure document trail, reduce the risk of VAT deduction challenges, and demonstrate a proactive approach to compliance.

Moreover, KSeF adoption brings operational advantages. It streamlines the invoicing process, reduces the need for paper records, and creates consistency in invoice format and content. Over time, this is likely to lead to faster VAT processing, fewer administrative errors, and lower audit risk.

Delaying KSeF implementation until the last possible moment might avoid penalties in the short term—but it can create real business disadvantages, both in terms of tax risk and customer relationships.