| (I-501, I-502) | |
| Displacement | 1590t surface, 1775t submerged |
|---|---|
| Length | 87.6m oa |
| Width | 7.5m |
| Draught | 5.4m |
| Machinery | 2-shaft diesel electoric and electoric motor, 2200+580bhp surface, 500shp submerged |
| Speed | 19.2kt surface, 6.8kt submerged |
| Armament | 6-533mm TT, 1-105mm/45cal gun, 1-37mm/83cal MG, 1-20mm MG |
| Complement | 57 |
| (I-503) | |
| Displacement | 1043t surface, 1290t submerged |
| Length | 73.0m oa |
| Width | 7.2m |
| Draught | 5.1m |
| Machinery | 2-shaft diesel and electoric motor, 3600bhp surface, 1100ihp submerged |
| Fuel | oil 108t |
| Speed | 17.4kt surface, 8kt submerged |
| Armament | 8-533mm TT, 2-100mm/47cal gun, 4-13.2mm MG (2x2) |
| Complement | 57 |
| (I-504) | |
| Displacement | 1175t surface, 1465t submerged |
| Length | 76.5m oa |
| Width | 6.8m |
| Draught | 4.7m |
| Machinery | 2-shaft diesel and electoric motor, 3600bhp surface, 1500ihp submerged |
| Fuel | oil 118t |
| Speed | 17.8kt surface, 8.2kt submerged |
| Armament | 8-533mm TT, 1-100mm/47cal gun, 4-13.2mm MG (2x2) |
| Complement | 57 |
| (I-505) | |
| Displacement | 1735t surface, 2143t submerged |
| Length | 89.8m oa |
| Width | 9.2m |
| Draught | 4.7m |
| Machinery | 2-shaft diesel and electoric motor, 2100bhp surface, 550ihp submerged |
| Speed | 16.4kt surface, 7kt submerged |
| Armament | 2-533mm TT, 1-105mm/45cal gun, 1-37mm/83cal gun, 1-20mm MG, 66 mines |
| Complement | 52 |
| (I-506) | |
| Displacement | 1585t surface, 1771t submerged |
| Length | 87.6m oa |
| Width | 7.5m |
| Draught | 5.4m |
| Machinery | 2-shaft diesel and electoric motor, 1400bhp surface, 500shp submerged |
| Speed | 15.8kt surface, 6.9kt submerged |
| Armament | 1-37mm/83cal MG, 1-20mm MG |
| Complement | 57 |
| (Ro-500) | |
| Displacement | 1102t surface, 1213t submerged |
| Length | 76.8m oa |
| Width | 6.8m |
| Draught | 4.7m |
| Machinery | 2-shaft diesel and electoric motor, 2200bhp surface, 500shp submerged |
| Speed | 18.2kt surface, 7.3kt submerged |
| Armament | 6-533mm TT, 1-105mm/45cal gun, 1-37mm/83cal MG, 1-20mm MG |
| Complement | 48 |
| (Ro-501) | |
| Displacement | 1126t surface, 1237t submerged |
| Length | 76.8m oa |
| Width | 6.9m |
| Draught | 4.7m |
| Machinery | 2-shaft diesel and electoric motor, 2200bhp surface, 500shp submerged |
| Speed | 18.2kt surface, 7.3kt submerged |
| Armament | 6-533mm TT, 1-105mm/45cal gun, 1-37mm/83cal MG, 1-20mm MG |
| Complement | 48 |
| Name | Plan | Builder | Laid down | Launch | Complete | ||
|---|---|---|---|---|---|---|---|
| I-501 | - | Ger Deschimag | ? | 1941.12.30 | 1942. 5. 9 | Ger U-181 | 1945. 5. 9 captured 1945. 7.15 SS1 (I-501) 1945.11.30 disc 1946. 2.12 scuttled |
| I-502 | - | Ger Deschimag | ? | 1943. 6. 5 | 1943.10. 7 | Ger U-862 | 1945. 5. 9 captured 1945. 7.15 SS1 (I-502) 1945.11.30 disc 1946. 2.12 scuttled |
| I-503 | - | It OTO La Spezia | 1938. 4.25 | 1939. 5.14 | 1939. 9.23 | It Commandante Capellini | 1943. 9.10 captured 1943 Ger UIT-24 1945. 5. 9 captured 1945. 7.15 SS1 (I-503) 1945.11.30 disc 1946. 4.16 scuttled |
| I-504 | - | It OTO La Spezia | 1939. 2.15 | 1940. 1. 6 | 1940. 5.15 | It Luigi Torelli | 1943. 9.10 captured 1943 Ger UIT-25 1945. 5. 9 captured 1945. 7.15 SS1 (I-504) 1946. 4.16 scuttled |
| I-505 | - | Ger Germaniawerft | ? | 1942.10. 6 | 1942.12.12 | Ger U-219 | 1945. 5. 9 captured 1945. 7.15 SS1 (I-505) 1945.11.30 disc 1947 BU |
| I-506 | - | Ger Deschimag | ? | 1942. 4. 8 | 1942. 9. 5 | Ger U-195 | 1945. 5. 9 captured 1945. 7.15 SS1 (I-506) 1945.11.30 disc 1947 BU |
| Ro-500 | - | Ger Germaniawerft | ? | 1941. 9.22 | 1941.12. 8 | Ger U-511 | 1943. 9.16 SS2 (Ro-500) 1945.11.30 disc 1946. 4.30 scuttled |
| Ro-501 | - | Ger Deutsche Werke | ? | 1943. 7. 7 | 1943.10.20 | Ger U-1224 | 1944. 2.15 SS2 (Ro-501) 1944. 5.13 sunk (action, off Azores Is.) [18.08N, 33.13W] 1944. 8.26 missing 1944.10.10 disc |