The Type AM (A Modified) submarine (巡潜甲型改二潜水艦 Junsen kō-gata kai-ni sensuikan, "Cruiser submarine type A modified 2"), also called I-13-class submarine was a pair of large, aircraft-carrying cruiser submarines built for the Imperial Japanese Navy (IJN) during World War II.
The Type AM submarines were versions of the preceding A2 class with the command facilities replaced by an enlarged aircraft hangar were fitted for a pair of Aichi M6A1 floatplane bombers. They displaced 3,661 tonnes (3,603 long tons) surfaced and 4,838 tonnes (4,762 long tons) submerged. The submarines were 113.7 meters (373 ft 0 in) long, had a beam of 11.7 meters (38 ft 5 in) and a draft of 5.9 meters (19 ft 4 in). They had a diving depth of 100 meters (330 ft).
Seven units were ordered, but only two were completed, while construction of two more was abandoned in March 1945. Construction of the remaining three submarines never started.