B-39 was a Project 641 (Foxtrot-class) diesel-electric attack submarine of the Soviet Navy. The "B" (actually "Б") in her designation stands for большая (bolshaya, "large")—Foxtrots were the Soviet Navy's largest non-nuclear submarines. In 2005 B-39 became a museum ship on display at the Maritime Museum of San Diego, California, United States. In October 2021 the decision was made to withdraw the deteriorating submarine from the collection and scrap it.

Her keel was laid down on 9 February 1962 at the Admiralty Shipyard in Leningrad (now known as Saint Petersburg). She was launched on 15 April 1967 and commissioned on 28 December 1967.