| Displacement | 1400t standard, 1785t surface, 2440t submerged |
|---|---|
| Length | 98.4m pp, 102.6m wl, 104.7m oa |
| Width | 8.2m |
| Draught | 4.58m |
| Machinery | 2-shaft diesel/electric motor, 9000bhp surface, 1800shp submerged |
| Speed | 23kt surface, 8.2kt submerged |
| Armament | 6-53cm TT, 1-10cm/50cal gun (I-71, 72, 73 1-12cm/45cal gun), 1-25mm AA |
| Complement | 60 - 84 |
| Name | Plan | Builder | Laid down | Launch | Complete | ||
|---|---|---|---|---|---|---|---|
| I-68 (I-168) | FY1931 | Kure NYd | 1931. 6.18 | 1933. 6.26 | 1934. 7.31 | SS1 | 1942. 5.20 renamed (I-168) 1943. 7.27 sunk (torpedoed, near Rabaul) [02.50S, 149.01E] 1943. 9.10 missing 1943.10.15 disc |
| I-69 (I-169) | FY1931 | Mitsubishi, Kobe | 1931.12.22 | 1934. 2.15 | 1935. 9.28 | SS1 | 1942. 5.20 renamed (I-169) 1944. 4. 4 lost (accident, Truk atoll) 1944. 6.10 disc |
| I-70 | FY1931 | Sasebo NYd | 1933. 1.25 | 1934. 6.14 | 1935.11. 9 | SS1 | 1941.12.10 sunk (air attack, near Hawaii) [23.45N, 155.35W] 1941.12.10 missing 1942. 3.15 disc |
| I-71 (I-171) | FY1931 | Kawasaki, Kobe | 1933. 2.15 | 1934. 8.25 | 1935.12.24 | SS1 | 1942. 5.20 renamed (I-171) 1944. 2. 1 sunk (action, Central Solomons) [05.37S, 154.14E] 1944. 3.12 missing 1944. 4.30 disc |
| I-72 (I-172) | FY1931 | Mitsubishi, Kobe | 1933.12.16 | 1935. 6.20 | 1937. 1. 7 | SS1 | 1942. 5.20 renamed (I-172) 1942.11.10 sunk (action, near Solomons) [10.13S, 611.09E] 1942.11.27 missing 1942.12.15 disc |
| I-73 | FY1931 | Kawasaki, Kobe | 1934. 4. 5 | 1935. 6.20 | 1937. 1. 7 | SS1 | 1942. 1.27 missing 1942. 1.29 sunk (action, near Hawaii) [28.24N, 178.35E] 1942. 3.15 disc |