If you are planning to stay in Poland for over 30 days, you are required to register in within 4 days of your arrival. You can register when you have a flat rental contract. For your visit to the Office, you should prepare: a renting agreement, a valid passport with a document that legalizes your stay, a completed form (if you want to register for a period longer than 3 months, registration for a period shorter than 3 months is made orally). Some offices also require the written agreement of registration in the flat from its owner or his / her appearance. Confirmation of registration is issued immediately and it is free.