INS Kalvari (S21) is the first of the six indigenous Scorpène-class submarines currently in service with the Indian Navy. It is a diesel-electric attack submarine which is designed by DCNS and was manufactured at Mazagon Dock Limited in Mumbai.

The Scorpène-class submarines are a class of diesel-electric attack submarines jointly developed by the French Naval Group and the Spanish company Navantia. It features diesel propulsion and an additional air-independent propulsion (AIP). It is now marketed as the Scorpène 2000.