The Kalvari-class is a class of six diesel-electric attack submarines operated by the Indian Navy (IN), formally classified as the Project-75 (P-75) submarines. It is an export derivative of the French-origin Scorpène-class submarine. The name is a namesake of the first submarines inducted into the IN in 1967. The current class was conceptualized in the late-1990s as part of a 30-year naval rearmament roadmap to replace the aging conventional fleet. The Ministry of Defence (MoD) placed an order for six units in 2005, with construction led by Mazagon Dock Limited (MDL) in Mumbai in collaboration with France's Naval Group. The lead vessel, INS Kalvari, was commissioned in December 2017, and the final submarine, INS Vagsheer, was commissioned on January 15, 2025.
The submarines are designed for superior stealth and can perform anti-surface warfare, anti-submarine warfare, intelligence gathering, and mine laying. They are equipped with the SUBTICS integrated combat system and feature six 533 mm weapon launching tubes. These tubes can fire SUT torpedoes or SM39 Exocet anti-ship missiles. The class connects to the planned follow-on program, Project-75I (P-75I), which aims for a key technological upgrade: the integration of a fuel-cell-based Air Independent Propulsion (AIP) system. This AIP system is also being retrofitted into the existing Kalvari-class submarines. A contract was signed on December 30, 2024, with MDL for the AIP integration, with the refit of the first submarine, INS Khanderi, scheduled from July 2026. On the same date, a contract was signed with Naval Group for the integration of the indigenous Electronic Heavy Weight Torpedo (EHWT) Takshak.