Project-75I (P-75I) is the Indian Navy’s programme to acquire six next-generation diesel-electric submarines fitted with air-independent propulsion (AIP), intended to significantly extend underwater endurance compared with the Navy’s existing Sindhughosh (Kilo) and Kalvari (Scorpene) classes.[1]
The P-75I boats are based on a next-generation variant of the German Type 214 submarine design. Construction is planned at Mazagon Dock Shipbuilders Limited (MDL), Mumbai, in partnership with Germany’s ThyssenKrupp Marine Systems (TKMS), selected as the sole qualified bidder in January 2025 following a prolonged, multi-year vendor-selection process. The submarines will displace approximately 3,000 tonnes and are designed for anti-surface warfare, anti-submarine warfare, ISR, special-forces support, and operations in both open-ocean and shallow littoral waters.[1]
Programme costs have risen substantially over time, from roughly ₹43,000 crore when first estimated in 2018 to approximately ₹70,000 crore by 2026. As of 2026, the programme has moved close to final government approval following years of delay in vendor and design selection, positioning it to eventually succeed/supplement the Kalvari-class as the Navy’s next mainline conventional submarine.[1]
| Type | Air-independent-propulsion (AIP) diesel-electric submarine |
| Design basis | Next-generation Type 214 (Germany) |
| Builder | Mazagon Dock Shipbuilders Ltd (MDL), with ThyssenKrupp Marine Systems (TKMS) |
| Planned fleet size | 6 submarines |
| Displacement | ~3,000 tonnes |
| Estimated cost (2026) | ~₹70,000 crore |
| Status (2026) | Near final government approval; TKMS selected as sole bidder Jan 2025 |