No visa, inside the EU
Poland and Spain are both in the EU, so you can live and work in Spain without a visa or work permit. A valid ID card or passport is enough.
The key step: if you stay longer than 3 months, register as an EU citizen (Certificado de Registro de Ciudadano de la UE) within 3 months of arriving. You get an NIE number, needed for work, a bank account and contracts. Also register at the town hall (empadronamiento).
Your checklist in Poland
- A valid ID card or passport.
- Documents in one folder: birth and marriage certificates, diplomas, work references, driving licence.
- Money for the start: a deposit (1 month's rent by law; the landlord may ask for an extra guarantee of at most 2 months' rent), the first rent and a few weeks of living costs.
- Tell your Polish bank you are moving and keep the app working, so you can pay bills at home.
- Set up Polish TV before you go, so it works from day one (how to watch Polish TV in Spain).