Document checklist
Iceland → Finland: Residence permit for an employed person (TTOL)
Whether you need a visa at all, according to official sources.
Not yet checked. This page was drafted from the sources listed below but hasn't passed verification yet. Double-check anything critical directly with the official source before you rely on it.
You likely don't need this permit
Nordic citizens don't need a residence permit to work in Finland and don't apply for EU registration. It is enough to register your personal details with the Digital and Population Data Services Agency.
Source: Finnish Immigration Service (Migri), Registering an EU citizen's right of residence