With Sweden's imminent accession, the Baltic Sea will become NATO waters - and Russia's leeway is dwindling. Only just under a tenth of the approximately 8,000 kilometer long coastline of the sea belongs to Russia - in the east of the Gulf of Finland and in front of the Kaliningrad exclave between Poland and Lithuania.
The alliance also increased its maritime patrols in October 2023 in response to a series of mysterious incidents in which undersea cables and gas pipelines were severed near Finland, Sweden and Estonia.