Type L submarine may refer to one of the following classes of submarines based on the British L-class submarine: * Japanese Type L submarine, a class of submarine for the Imperial Japanese Navy; built in the mid-1920s and active in World War II * Soviet Type L submarine, an alternate name for the Soviet Navy's Leninets-class submarine; built between 1931–1941 and active during World War II; most decommissioned by the 1950s