| Displacement | 1970t standard, 2135t surface, 2791t submerged |
|---|---|
| Length | 94.0m pp, 93.9m wl, 97.5m oa |
| Width | 9.2m |
| Draught | 5.0m |
| Machinery | 2-shaft diesel/electric motor, 6000bhp surface, 2600shp submerged |
| Speed | 18kt surface, 8kt submerged |
| Armament | 6-53cm TT, 2-14cm/40cal gun |
| Complement | 92 |
| Name | Plan | Builder | Laid down | Launch | Complete | ||
|---|---|---|---|---|---|---|---|
| I-1 (SS-74) | FY1923 | Kawasaki, Kobe | 1923. 3.12 | 1924.10.15 | 1926. 3.10 | SS1 | 1943. 1.29 sunk (action, off Guadalcanal) [09.13S, 159.40E] 1943. 4. 1 disc |
| I-2 (SS-75) | FY1923 | Kawasaki, Kobe | 1923. 8. 6 | 1925. 2.23 | 1926. 7.24 | SS1 | 1944. 4. 7 sunk (action, W of Hannover I.) [02.17S, 149.14E] 1944. 5. 4 missing 1944. 6.10 disc |
| I-3 (SS-76) | FY1923 | Kawasaki, Kobe | 1923.11. 1 | 1925. 6. 8 | 1926.11.30 | SS1 | 1942.12. 9 sunk (action, off Guadalcanal) [09.12S, 159.42E] 1943. 1.20 disc |
| I-4 | FY1923 | Kawasaki, Kobe | 1926. 4.17 | 1928. 5.22 | 1929.12.24 | SS1 | 1942.12.20 sunk (torpedoed, Central Solomons) [08.32S, 148.17E] 1943. 1. 5 missing 1943. 3. 1 disc |