Poland: New Rules for Determining Seniority in the Private Sector

As of May 1, 2026, new regulations regarding the determination of seniority (length of service) for private-sector employers have come into effect. These changes expand the catalog of periods included when calculating employee entitlements, such as annual leave allowance and seniority bonuses.

The new regulations allow for the inclusion of professional activities other than employment under an employment contract. This includes, among others, running a business, performing tasks under mandate or agency contracts, and certain periods of cooperation in conducting business.

The changes include:

• work abroad: counting documented periods of work performed abroad toward seniority.
• recalculation of entitlements: the possibility to recalculate employee benefits, including increasing the annual leave allowance.
• an obligation to include these new periods when determining company seniority.
• the requirement to confirm professional activity periods via a certificate issued by the social insurance institution (zus).

Employees already employed in private companies on the date the changes took effect will have 24 months to document the periods eligible for inclusion in their seniority.