India commissions INS Aridhaman, strengthens sea-based nuclear deterrent with third SSBN

Visakhapatnam, April 4. India on April 3 inducted INS Aridhaman, its third indigenously built nuclear-powered ballistic missile submarine, marking a major milestone in the country’s sea-based nuclear deterrent capability.

With this commissioning, India now fields three SSBNs (ship submersible ballistic nuclear) of the Arihant class – INS Arihant (inducted in 2016), INS Arighaat (2024) and Aridhaman. These vessels are central to India’s nuclear triad – the ability to launch nuclear weapons from land, air and sea.

Powered by nuclear reactors, these submarines can remain submerged for extended durations, making them the most survivable leg of India’s deterrent posture. While India’s nuclear doctrine rules out a first strike, SSBNs provide the assured capability for a retaliatory response while remaining concealed underwater.

Strategic analysts note that the induction of Aridhaman gives India the numbers required to maintain a “continuous at-sea deterrent”, ensuring that at least one SSBN can remain on armed patrol at all times. This places India in a select group of nations – alongside China, France, Russia, United Kingdom and United States – with this capability.

Aridhaman is expected to be armed with the 750-km range K-15 submarine-launched ballistic missile as well as the longer-range K-4 missile with a reach of about 3,500 km, both capable of carrying nuclear warheads.

The submarine is part of India’s classified Advanced Technology Vessel (ATV) programme. Compared to its predecessors, Aridhaman is longer and features eight vertical launch tubes instead of four, effectively doubling its missile-carrying capacity.

The submarine’s hull was fabricated by Larsen & Toubro and the vessel was built in Visakhapatnam. It is powered by an indigenous 83 MW pressurised light-water reactor developed by the Bhabha Atomic Research Centre.

Aridhaman is also equipped with improved sonar suites, indigenous communication systems and refined hydrodynamic design to minimise acoustic signature, enhancing its stealth during deep-sea patrols.

Defence Minister Rajnath Singh, who was in Visakhapatnam earlier in the day for the commissioning of INS Taragiri, posted a brief message on social media describing Aridhaman as “not just a word, but a power.”

Apart from its indigenous SSBN fleet, India is also in the process of acquiring a nuclear-powered attack submarine from Russia, expected to join the Navy by 2027. Unlike SSBNs, such submarines are not designed to carry nuclear missiles but are meant for offensive and escort roles.