The was a class of submarine in the Imperial Japanese Navy (IJN), which served during the Second World War. The Type-A submarines were built to take a role of the command ships for submarine squadrons. For this reason they had equipment for a headquarters, better radio facilities and a floatplane.
The Type-A submarines were divided into four classes:
See main article: Type A1 submarine. Project number S35Ja. Their design was based on the Junsen III (I-7 class). Three boats were built in 1938-42 under the Maru 3 Programme (Boat # 35 - 36) and Maru 4 Programme (Boat # 138).
| Boat No. | Boat | Builder | Laid down | Launched | Completed | Results | Fate |
| 35 | [1] | Kure Naval Arsenal | 25-01-1938 | 20-05-1939 | 13-02-1941 | Sank USS Lahaina 12-12-1941 | Sunk by at Kiska 52.1333°N 215°W 13-06-1943. |
| 36 | Kawasaki-Kōbe Shipyard | 07-06-1938 | 20-09-1939 | 31-10-1941 | Sank Panamanian merchant ship Donerail 10-12-1941 Sank USS Melvin H. Baker 05-06-1942 Sank Panamanian merchant ship Atlantic Gulf 06-06-1942 Sank RMS King Lud 08-06-1942 Sank RMS Queen Victoria 28-06-1942 Sank USS Express 30-06-1942 Sank Greek merchantman Nymphe 06-07-1942 Sank RMS Hartismere 08-07-1942 Sank Dutch merchant ship Alchiba 09-07-1942 Sank USS Samuel Gompers 30-01-1943 Sank USS Gulfwave 01-03-1943 Sank Norwegian merchantman Alcides 22-07-1943 Sank Norwegian merchant ship Bramora 14-09-1943 Sank USS Elias Howe 24-09-1943 Sank Norwegian merchant ship Storvixen 01-10-1943 Sank Norwegian merchantman Anna Knudsen 02-10-1943 Sank RMS Congella 24-10-1943 Sank or damaged unknown warship 02-07-1944 | Sunk by and east of Saipan 15.4333°N 195°W 04-07-1944. | |
| 138 | Kawasaki-Kōbe Shipyard | 10-04-1940 | 28-02-1941 | 16-05-1942 | Sank Greek merchant ship George S. Livanos 20-07-1942 Sank USS Coast Farmer 21-07-1942 Sank USS William Dawes 22-07-1942 Damaged 20-07-1943 Damaged USS Matthew Lyon 11-08-1943 | Lost in an accident or sunk by a mine near Funafuti January 1944. | |
Project number S35B. Five boats were planned under the Maru Tsui Programme (Boat # 620 - 621) and the Kai-Maru 5 Programme (Boat # 5091 - 5093). They were equipped with less powerful diesel engines which shortened the time needed to build them. Only one boat,, was completed to the original design. The I-13 and the later boats were converted to a new submarine class (I-13 class), because the number of I-400 class boats was reduced.
| Boat No. | Boat | Builder | Laid down | Launched | Completed | Results | Fate |
| 620 | Kawasaki-Kōbe Shipyard | 05-11-1942 | 03-08-1943 | 25-05-1944 | Sank USS John A. Johnson 30-10-1944 | Sunk by minesweeper USS Ardent on 13-11-1944. | |
| 621 | I-13 | Kawasaki-Kōbe Shipyard | 04-02-1943 | Converted to the I-13 class in October 1943. | |||
| 5091 | I-14 | Kawasaki-Kōbe Shipyard | 18-05-1943 | ||||
| 5092 | I-15 | Kawasaki-Senshū Shipyard | 30-04-1943 | ||||
| 5093 | I-1 | Kawasaki-Senshū Shipyard | 24-06-1943 | ||||
Project number S35C. Four boats were planned under the Maru Tsui Programme (Boat # 621) and the Kai-Maru 5 Programme (Boat # 5091 - 5093). However, four boats were converted to new submarine class (I-13 class), because a number of submarines of the I-400 class were cancelled. They had a large hangar and were equipped with bulges to be able to operate 2 × special Aichi M6A1 Seiran attack bombers. The headquarters institutions were removed.
| Boat No. | Boat | Builder | Laid down | Launched | Completed | Results | Fate |
| 621 | Kawasaki-Kōbe Shipyard | 04-02-1943 | 30-11-1943 | 16-12-1944 | Sunk by, and aircraft from northeast of the Ogasawara Islands 16-07-1945. | ||
| 5091 | Kawasaki-Kōbe Shipyard | 18-05-1943 | 14-03-1944 | 14-03-1945 | Captured by 27-08-1945, decommissioned 15-09-1945, sunk as a target off the Hawaiian Islands 28-05-1946. | ||
| 5092 | I-15 | Kawasaki-Senshū Shipyard Kawasaki-Kōbe Shipyard (after launch) | 30-04-1943 | 12-04-1944 | Converted to a tanker submarine in June 1945;[2] 90% complete; scrapped in 1945. | ||
| 5093 | I-1 | Kawasaki-Kōbe Shipyard Kawasaki-Senshū Shipyard (after launch) | 24-06-1943 | 10-06-1944 | 70% complete; Sunk by a typhoon on 18-09-1945; later salvaged and scrapped. | ||
Project number S48. Three boats were planned under the Kai-Maru 5 Programme. However, all boats were cancelled in late 1943, because the IJN turned its attention to the construction of in 1945.
| Boat No. | Boat | Builder | Laid down | Launched | Completed | Fate |
| 5094 - 5096 | Cancelled in 1943. | |||||
| Type | Type-A (I-9) | Type-A Mod.1 (I-12) | Type-A Mod.2 (I-13) | V21 Type | |
| Displacement | Surfaced | 2434LT | 2390LT | 2620LT | 2330LT |
| Submerged | 4150LT | 4172LT | 4762LT | No data | |
| Length (overall) | 113.7m (373feet) | 113.7m (373feet) | 113.7m (373feet) | 111m (364feet) (waterline) | |
| Beam | 9.55m (31.33feet) | 9.55m (31.33feet) | 11.7m (38.4feet) | 9.82m (32.22feet) | |
| Draft | 5.36m (17.59feet) | 5.36m (17.59feet) | 5.89m (19.32feet) | 5.5m (18feet) | |
| Depth | 8.3m (27.2feet) | 8.3m (27.2feet) | 8.3m (27.2feet) | No data | |
| Power plant and shaft | 2 × Kampon Mk.2 Model 10 diesels 2 shafts | 2 × Kampon Mk.22 Model 10 diesels 2 shafts | 2 × Kampon Mk.22 Model 10 diesels 2 shafts | 2 × Kampon Mk.2 Model 10 diesels 2 shafts | |
| Power | Surfaced | 12,400 bhp | 4,700 bhp | 4,700 bhp | 11,000 bhp |
| Submerged | 2,400 shp | 1,200 shp | 600 shp | 2,400 shp | |
| Speed | Surfaced | 23.5kn | 17.7kn | 16.7kn | 22.4kn |
| Submerged | 8kn | 6.2kn | 5.5kn | 8kn | |
| Range | Surfaced | 16000abbr=onNaNabbr=on at 16kn | 22000abbr=onNaNabbr=on at 16kn | 21000abbr=onNaNabbr=on at 16kn | 16000abbr=onNaNabbr=on at 16kn |
| Submerged | 90abbr=onNaNabbr=on at 3kn | 75abbr=onNaNabbr=on at 3kn | 60abbr=onNaNabbr=on at 3kn | 80abbr=onNaNabbr=on at 3kn | |
| Test depth | 100m (300feet) | 100m (300feet) | 100m (300feet) | 100m (300feet) | |
| Fuel | 878 tons | 917 tons | 917 tons | 880 tons | |
| Complement | 104 | 112 | 108 | No data | |
| Armament (initial) | • 6 × 5330NaN0 Torpedo tubes (6 × front) • 18 × Type 95 torpedoes • 1 × 140mm L/40 11th Year Type Naval gun[3] • 4 × Type 96 25mm AA guns | • 6 × 5330NaN0 TTs (6 × front) • 18 × Type 95 torpedoes • 1 × 140mm L/40 11th Year Type Naval gun • 4 × Type 96 25mm AA guns | • 6 × 5330NaN0 TTs (6 × front) • 12 × Type 95 torpedoes • 1 × 140mm L/40 11th Year Type Naval gun • 10 × Type 96 25mm AA guns | • 6 × 5330NaN0 TTs (6 × front) • 18 × torpedoes • 1 × 140 mm Naval gun • 4 × 25mm AA guns | |
| Aircraft and facilities | • Catapult and hangar • 1 × Watanabe E9W1 Slim seaplane | • Catapult and hangar • 1 × Yokosuka E14Y2 Glen seaplane | • Catapult and hangar • 2 × Aichi M6A1 Seiran floatplane | • Catapult and hangar • 1 × floatplane | |