High Quality Content by WIKIPEDIA articles! The Black Sea Fleet (Russian: Черноморский Флот) is a large operational-strategic sub-unit of the Russian (and formerly Soviet) Navy, operating in the Black Sea and the Mediterranean Sea since the late 18th century. Its ships are based in various harbors of the Black Sea and the Sea of Azov while its aviation and infrastructure is based in various locations in Crimea, Ukraine and Krasnodar Krai, Russia.