The French submarine Marsouin was a built for the French Navy in the mid-1920s. Laid down in November 1922, it was launched in December 1924 and commissioned in September 1927. It escaped from Toulon on 27 November 1942 and joined the Free French Naval Forces; it was later disarmed at Oran in April 1944, and stricken on 28 February 1946.
long, with a beam of and a draught of , Requin-class submarines could dive up to . The submarine had a surfaced displacement of and a submerged displacement of . Propulsion while surfaced was provided by two diesel motors and two electric motors. The submarines' electrical propulsion allowed it to attain speeds of while submerged and on the surface. Their surfaced range was at , and at , with a submerged range of at .