Project-75(I), or P-75(I), is a major military acquisition program of the Indian Navy, classified as a scheme or initiative, for the planned procurement and indigenous construction of six new-generation conventional attack submarines (SSKs). The initiative was originally conceived in 1997 and formally initiated with the Acceptance of Necessity (AoN) in November 2007. Its purpose is to replace the Indian Navy's aging fleet, particularly the Sindhughosh-class submarines, and is a key part of the 30-year Submarine-building Perspective Plan approved by the Cabinet Committee on Security (CCS) in 1999.
The project is being executed under the Strategic Partnership (SP) Model of the Defence Acquisition Procedure (DAP), which aims to build indigenous capacity by mandating a partnership between an Indian Strategic Partner (SP) and a foreign Original Equipment Manufacturer (FOEM). The Defence Acquisition Council (DAC) approved the project under the SP Model in January 2019, making it the second project to be pursued under this policy after the Naval Utility Helicopter (NUH) project. A core technical requirement for the submarines is the inclusion of a Fuel-Cell based Air-Independent Propulsion (AIP) plant for significantly extended underwater endurance.
The Ministry of Defence (MoD) issued the Request for Proposal (RFP) in July 2021. Recently, the process narrowed down to a single bidder after the L&T-Navantia alliance was reportedly found non-compliant due to a lack of "sea-proven AIP". The sole remaining bid is a partnership between the state-owned Mazagon Dock Shipbuilders Limited (MDL) and Germany's ThyssenKrupp Marine Systems (TKMS), who signed a Memorandum of Understanding (MoU) in June 2023. This partnership, which proposes the Type 214 submarine design, is currently in the commercial negotiation phase with the MoD, with the estimated cost being around ₹70,000 crore. P-75(I) is a successor to Project-75 (Kalvari-class) and is central to India's 'Atmanirbharta' (self-reliance) vision in defence.