India’s next-generation S-5 ballistic missile submarine program has entered a significant development phase, with steel-cutting activities for the first vessel reportedly commencing at the Shipbuilding Centre in Visakhapatnam. While earlier plans frequently referenced a fleet of six submarines, current indications suggest that the Indian Navy is focusing on a primary batch of four S-5 boats, with additional units remaining a future possibility. The 13,500-ton submarines will be substantially larger than the Arihant-class and are expected to form the backbone of India’s sea-based nuclear deterrent. Simultaneous construction of the first two submarines has reportedly been approved to accelerate delivery schedules and maintain industrial momentum. The Navy appears confident that four highly capable S-5 submarines, supported by enlarged Arihant-class vessels, can sustain continuous deterrence patrols. Future planning may involve an enlarged “S-5 Plus” variant or an entirely new “S-6” design featuring greater missile capacity, improved reactor performance, and enhanced stealth technologies. The first S-5 submarine is expected to enter service around 2033–34 and will carry advanced K-series submarine-launched ballistic missiles, strengthening India’s nuclear triad and second-strike capability.
