Finland joins NATO as the alliance’s 31st member

Finland became NATO’s 31st member on 4 April 2023, depositing its instrument of accession with the United States at the alliance’s Brussels headquarters.

Northern Europe’s defence framework

Accession brought Finland into the alliance’s collective defence arrangements and its political decision-making. The change gave NATO a member on Russia’s northern frontier and tied Finnish security planning to that of its allies. The central shift was institutional: Finland moved from cooperation with the alliance to participation in its common defence commitments.