Santorre di Santarosa was one of four Bandiera-class submarines built for the Regia Marina (Royal Italian Navy) during the late 1920s.

[1] For surface running, the boats were powered by two 1,500-brake-horsepower (1,119 kW) diesel engines, each driving one propeller shaft.

They were also armed with a single 102-millimeter (4 in) deck gun forward of the conning tower for combat on the surface.

[1][2] Santorre Santarosa was laid down by Odero-Terni-Orlando at their Muggiano shipyard in 1928, launched on 22 October 1929 and completed later that year.

[3] During the Spanish Civil War, Santorre Santarosa was attempting to attack the 7,932-gross register ton (GRT) tanker SS Campeador during nightfall on 11 August 1937 off Ras el Mustafa, French Tunisia, when the Italian destroyer Saetta torpedoed and sank the tanker before the submarine could reach firing position.