Kairyū-class submarine

	A Kairyu "Sea Dragon" in the Aburatsubo inlet.
Class overview
Operators	Imperial Japanese Navy
Preceded by	Kō-hyōteki-class submarine
Succeeded by	Kaiten
Built	1943-1945
In commission	1943-1945
Planned	760
Completed	200–213 (sources vary)
Active	0
Preserved	2
General characteristics
Type	midget submarine
Displacement	19.3 t (21.3 short tons)
Length	17.2 m (56 ft 5 in)
Beam	1.3 m (4 ft 3 in)
Height	1.3 m (4 ft 3 in)
Propulsion	Surface: 64 kW (86 hp) diesel engine; Submerged: 60 kW (80 hp) electric engine;
Speed	Surface speed: 13 km/h (7.0 kn); Submerged speed: 19 km/h (10 kn);
Range	830 km (450 nmi) at 10 km/h (5.4 kn) surfaced; 70 km (38 nmi) at 5.5 km/h (3.0 kn) submerged;
Complement	2
Armament	2 × 450 mm (18 in) torpedoes and a 600 kg (1,300 lb) explosive charge

The Kairyu (海龍, Kairyū; "Sea Dragon") was a class of midget submarines of the Imperial Japanese Navy, designed in 1943–1944, and produced from the beginning of 1945. These submarines were meant to meet the invading American naval forces upon their anticipated approach of Tokyo.