NEW DELHI: India on Friday commissioned its third nuclear-powered ballistic missile submarine (SSBN), INS Aridhaman, a key step towards establishing continuous at-sea nuclear deterrence and strengthening the most survivable leg of its strategic triad.
Earlier in the day, Defence Minister Rajnath Singh hinted at the commissioning with a terse post on X, “It’s not words but power, ‘Aridhaman’!”
Sources confirmed Aridhaman has been inducted, following INS Arihant (2016) and INS Arighaat (2024), taking India’s operational SSBN fleet to three for the first time. This meets the minimum requirement for sustained deterrent patrol cycles, with at least one submarine deployed at all times while others undergo maintenance and training.
Aridhaman displaces an estimated 6,500 to 7,000 tonnes and can carry up to eight K-4 SLBMs or a greater number of shorter-range K-15 missiles depending on mission requirements. SSBNs are considered the most dependable second-strike capability given their stealth and survivability, forming the bedrock of India’s nuclear doctrine of credible minimum deterrence and no-first-use.
India currently operates a submarine fleet of around 17 boats, including 3 SSBNs and the rest diesel-electric platforms such as the Kalvari-class, Kilo-class and Shishumar-class submarines.
Follow-on SSBNs are already in development, including an improved S4* variant and the larger S5-class SSBNs, which are expected to carry longer-range missiles capable of covering targets deep across the Asian landmass.
The Navy has also revived its long-pending plan for at least six nuclear-powered attack submarines (SSNs) under Project 77, with work on two underway.
Unlike SSBNs built for concealment and strategic deterrence, SSNs are hunter-killer platforms armed with torpedoes and cruise missiles for anti-submarine warfare and sea denial.
India does not currently operate a SSN. It earlier leased an Akula-class submarine from Russia and is expected to receive another under the Chakra III arrangement as an interim capability.
In comparison, China operates a significantly larger and more mature undersea nuclear fleet, with at least six Jin-class SSBNs and around six to eight Shang-class nuclear-powered attack submarines, alongside a large conventional submarine force of over 50 vessels, including Yuan-class and Song-class submarines.
Pakistan, on the other hand, does not possess nuclear-powered submarines but is pursuing a rudimentary sea-based deterrent by adapting the Babur-3 nuclear-capable cruise missile for deployment on its Agosta-90B submarines, while also inducting Chinese-origin Hangor-class (Yuan-class derivative) diesel-electric boats.