Which deadlines must you track after hiring a foreigner?

Seven deadlines, and not one of them reminds you by itself. After the start you watch:

• the residence document's validity — and with an oświadczenie also the 24-month limit;
• periodic medicals;
• the end of a fixed-term contract;
• carried-over leave until 30.09 — unused, it is an employer offence;
• PPK re-enrolment every 4 years (the nearest: early 2027 — opt-out declarations must be collected again);
• ZCNA deregistration when the employee's child turns 18 or 26;
• the equivalent for unused leave after employment ends — at the latest within 10 days of the end, if the payday fell earlier (art. 171 § 4–5 of the Labour Code).