The Junsen type submarines were divided into four classes:
See main article: article and Type J1 submarine. Four boats were built in 1923-1929. Genealogy of the large-size submarine in the IJN began with . Japan received six U-boats from Germany as reparations of World War I. The IJN copied, one of the six, producing the I-21-class minelayer submarine. The IJN could not find an optimal design of fleet submarine, so they and Kawasaki Heavy Industries sent many technical officers to the United Kingdom and Germany and got drawings of advanced submarines. The British L class became the Kaidai I, the K class became the Kaidai II and U-142 become Junsen I.
| Boat | Builder | Laid down | Launched | Completed | Results | Fate |
| [1] | Kawasaki Shipbuilding | 12-03-1923 | 15-10-1924 | 10-03-1926 | Damaged 31-12-1941 Sank Dutch merchant ship Siantar 03-03-1942 | Sunk by and at Guadalcanal 29-01-1943. |
| Kawasaki Shipbuilding | 06-08-1923 | 23-02-1925 | 24-07-1926 | Sank Dutch merchant ship Parigi 01-03-1942 Sank RMS Chilka 11-03-1942 | Sunk by north of Rabaul -2.2833°N 163°W 07-04-1944. | |
| Kawasaki Shipbuilding | 01-11-1924 | 08-06-1925 | 30-11-1926 | Sank RMS Elmdale 07-04-1942 Sank RMS Fultala 08-04-1942 | Sunk by USS PT-59 at Kamimbo 09-12-1942. | |
| Kawasaki Shipbuilding | 17-04-1926 | 22-05-1928 | 24-12-1929 | Sank Norwegian merchant ship Hoegh Merchant 14-12-1941 Sank Dutch merchant ship Ban Ho Guan 28-02-1942 Sank USS Washingtonian 06-04-1942 Damaged unknown sailing boat 10-04-1942 Damaged 27-09-1942 | Sunk by southeast of Rabaul -5.0333°N 185°W 20-12-1942. | |
This is a type which added a floatplane to the Junsen I.
| Boat | Builder | Laid down | Launched | Completed | Results | Fate |
| Kawasaki Shipbuilding | 30-10-1929 | 19-06-1931 | 31-07-1932 | Sunk by east of Saipan 13.0167°N 209°W 19-07-1944. | ||
Project number S32. This is a type which added a catapult to the Junsen I Mod. She was built in 1931 under the 1st Naval Armaments Supplement Programme (Maru 1).
Project number S33. These boats combined the good points of the Junsen II and the Kaidai V. They were built in 1934 under the Maru 2 Programme. Junsen III became a 'typeship' for the Type-A, B and C.
| Boat | Builder | Laid down | Launched | Completed | Results | Fate |
| Kure Naval Arsenal | 12 September 1934 | 3 July 1935 | 31 March 1937 | Sank Dutch merchant ship Le Maire 04-03-1942 Sank RMS Glenshiel 03-04-1942 Sank USS Arcata 15-07-1942 | Damaged by at Kiska 21 June 1943. Scuttled 5 July 1943. | |
| Kawasaki-Kōbe Shipyard | 11-10-1934 | 20-07-1936 | 05-12-1938 | Sank Dutch merchant ship Tjisalak 26-03-1944 Sank RMS City of Adelaide 30-03-1944 Sank Australian merchant ship Nellore 29-06-1944 Sank USS Jean Nicolet 02-07-1944 | Sunk by southeast of Okinawa Island 25.4833°N 163°W 31-03-1945. | |
| Type | Junsen I (I-1) | Junsen I Mod. (I-5) | Junsen II (I-6) | Junsen III (I-7) | |
| Displacement | Surfaced | 1970LT | same as Junsen I | 1900LT | 2231LT |
| Submerged | 2791LT | 3061LT | 3583LT | ||
| Length (overall) | 97.5m (319.9feet) | 98.5m (323.2feet) | 109.3m (358.6feet) | ||
| Beam | 9.22m (30.25feet) | 9.06m (29.72feet) | 9.1m (29.9feet) | ||
| Draft | 4.94m (16.21feet) | 5.31m (17.42feet) | 5.26m (17.26feet) | ||
| Depth | 7.58m (24.87feet) | 7.58m (24.87feet) | 7.7m (25.3feet) | ||
| Power plant and shaft | 2 × Rauschenbach Mk.2 diesels 2 shafts | 2 × Kampon Mk.1A Model 7 diesels 2 shafts | 2 × Kampon Mk.1A Model 10 diesels 2 shafts | ||
| Power | Surfaced | 6,000 bhp | 8,000 bhp | 11,200 bhp | |
| Submerged | 2,600 shp | 2,600 shp | 2,800 shp | ||
| Speed | Surfaced | 18.8kn | 20kn | 23kn | |
| Submerged | 8.1kn | 7.5kn | 8kn | ||
| Range | Surfaced | 24400abbr=onNaNabbr=on at 10kn | 20000abbr=onNaNabbr=on at 10kn | 14000abbr=onNaNabbr=on at 16kn | |
| Submerged | 60abbr=onNaNabbr=on at 3kn | 65abbr=onNaNabbr=on at 3kn | 80abbr=onNaNabbr=on at 3kn | ||
| Test depth | 75m (246feet) | 80m (260feet) | 100m (300feet) | ||
| Fuel | 545 tons | 580 tons | 580 tons | 800 tons | |
| Complement | 75 | 75 | 80 | 100 | |
| Armament (initial) | • 6 × 5330NaN0 torpedo tubes (4 × bow, 2 × aft) • 22 × Type 89 torpedoes • 2 × 140mm L/40 11th Year Type Naval guns[2] • 1 × 7.7 mm machine gun | • 6 × 5330NaN0 torpedo tubes (4 × bow, 2 × aft) • 20 × Type 89 torpedoes • 2 × 127mm L/40 Type 88 AA guns • 1 × 7.7 mm machine gun | • 6 × 5330NaN0 torpedo tubes (4 × bow, 2 × aft) • 17 × Type 89 torpedoes • 1 × 127mm L/40 Type 88 AA gun • 1 × 13.2mm AA gun | • 6 × 5330NaN0 torpedo tubes (6 × bow) • 20 × Type 89 torpedoes • 2 × 140 mm L/40 11th Year Type Naval guns • 2 × 13 mm AA guns | |
| Aircraft and facilities | • Hangar • 1 × Yokosuka E6Y1 | • Catapult and hangar • 1 × Yokosuka E6Y1 | • Catapult and hangar • 1 × Watanabe E9W1 Slim | ||