The Type C3 submarine (巡潜丙型改潜水艦, Junsen Hei-gata kai sensuikan, "Cruiser submarine type C modified"), also called I-52-class submarine (伊五十二型潜水艦, I-go-jū-ni-gata sensuikan) were operated by the Imperial Japanese Navy, designed and built by Mitsubishi Corporation, between 1943 and 1944, as cargo carriers.

Class overview
Builders	Mitsubishi
Operators	Imperial Japanese Navy
Preceded by	Type C submarine
Built	1942–1944
In commission	1943–1945
Planned	20
Completed	3
Lost	2
General characteristics
Displacement	2,095 tonnes standard 2,564 tonnes surfaced 3,644 tonnes submerged
Length	356 ft 6 in (108.66 m)
Beam	30 ft 6 in (9.30 m)
Draft	16 ft 9 in (5.11 m)
Propulsion	Diesel-electric 2 diesels, 4,700 hp (3.5 MW) surfaced Electric motors, 1,200 hp (895 kW) submerged
Speed	17.75 knots (32.87 km/h) surfaced 6.5 knots (12 km/h) submerged
Range	21,000 nmi (39,000 km) at 16 kn (30 km/h)
Test depth	100 m (330 ft)
Complement	94 officers and men
Armament	2 × 140 mm (5.5 in)/40 calibre deck gun 6 × 533 mm (21 in) torpedo tubes (bow) 19 × Type 95 torpedoes

The Japanese constructed only three of these during World War II, although twenty were planned.^[1]

• I-52 was laid down on 18 March 1942, and she was commissioned on 28 December 1943 into the 11th Submarine Squadron. After training in Japan she was selected for a Yanagi (exchange) mission to Germany. She was sunk on 24 June 1944 by aircraft from USS Bogue (CVE-9) 800 mi (1,300 km) southwest of the Azores. Her cargo consisted of rubber, gold, quinine, and Japanese engineers to Germany.
• I-53 survived the war, but she was scuttled by the US Navy off the Gotō Islands in 1946.
• I-55 was sunk after three months in commission by destroyer USS Gilmer and destroyer escort USS William C. Miller off Saipan on 14 July 1944.