Her first war patrol was in the Mediterranean Sea from 15 August to 3 September 1940. Michele Bianchi sailed on 27 October 1940 and reached the Strait of Gibraltar on 3 November. Her attempted transit to the Atlantic was detected by Royal Navy forces, and Michele Bianchi took refuge in the neutral port of Tangier. Michele Bianchi left Tangier on 12 November and reached Bordeaux on 18 December 1940.
Michele Bianchi sank four ships on her first BETASOM patrol from Bordeaux; but the next patrol from 30 April to 30 May 1941 was unsuccessful. After sailing from Bordeaux on 4 July 1941, Michele Bianchi was torpedoed and sunk with all hands by HMS Tigris on 5 July.[1]
