Generally, students from EU/EEA countries don't need to apply for a student visa but they need to register their stay in Poland. You have to do this if you intend to stay for longer than three months. ... The process is cost-free and you will get a certificate of registration that proves your right to stay in Poland.
If you are a citizen of an EU member state the only thing you need to have to enter Poland is a valid travel document or a document confirming identity and citizenship (i.e. your national ID). However, if you wish to travel abroad during your stay in Poland it is a good idea to have a passport with you,
