Barents Sea
The southern half of the Barents Sea stays ice-free year round due to the warmth brought by the North Atlantic drift. This includes the ports of Murmansk in Russia and Vardø in Norway. In September, the entire Barents Sea is mostly ice-free.  Until the end of the Winter War, Finland's territories reached the Barents Sea.  This made the harbor at Petsamo Finland's only ice-free winter harbor.