What Sweden's submarines bring to NATO

The Swedish submarine HMS Gotland lies in a port at the naval base of Karlskrona, Sweden May 25, 2023. REUTERS/Tom Little/File Photo

KARLSKRONA, Sweden (Reuters) - When Sweden joins NATO, it will help the alliance redress its vulnerability in northwest Europe – the Baltic Sea, a shared waterway with Russia with a bottleneck for access to ports in eight states including Germany.

Sweden's key to keeping the waters navigable in a conflict is its world-leading submarine fleet, which analysts say holds some of the most advanced conventional submarines ever built.