India Commissions Third SSBN, Bolstering Sea-Based Nuclear Deterrence

India has quietly commissioned its third nuclear-powered ballistic missile submarine, INS Aridaman, marking a significant expansion of its sea-based nuclear capability and reinforcing the credibility of its nuclear triad.

The 7,000-tonne submarine was commissioned in Visakhapatnam on Friday without public glare, as Defence Minister Rajnath Singh hinted at the development with a brief post on X, stating: “It’s not words but power, ‘Aridaman’!”

शब्द नहीं शक्ति है, ‘अरिदमन’!

— Rajnath Singh (@rajnathsingh) April 3, 2026

With the induction of Aridaman, India now operates three Ship Submersible Ballistic Nuclear submarines (SSBNs) – joining INS Arihant and INS Arighat – allowing, for the first time, sustained deployment cycles at sea. It significantly strengthens India’s nuclear deterrent by ensuring that at least two platform remains on patrol at all times.

The commissioning comes alongside the Minister’s visit to attend the commissioning of the stealth frigate INS Taragiri, underscoring a broader push to enhance naval capabilities.

India’s SSBN programme remains among its most closely guarded strategic projects. INS Arihant, commissioned in 2016, marked the country’s entry into an exclusive group of nations with operational nuclear-powered ballistic missile submarines. It was followed by INS Arighat, inducted in 2024, which added depth to underwater deterrence patrols.

INS Aridaman, understood to feature a larger hull and improved endurance over its predecessors, is capable of carrying a greater number of longer-range nuclear-tipped ballistic missiles. It enhances India’s assured second-strike capability, a cornerstone of its nuclear doctrine.

Navy Chief Admiral Dinesh Tripathi had indicated last year that the submarine was in advanced stages of trials, with commissioning expected around mid-2026.
Work is already underway on the next generation of SSBNs, including the S-4*, which is expected to be larger and more capable. The S-4* platform is likely to carry K-4 ballistic missiles with a strike range of around 3,500 km which was tested in December last year.

In parallel, India is also strengthening its attack submarine fleet. The Navy is set to induct Chakra III, a Russian-origin Akula-class nuclear-powered attack submarine, expected around 2027–28. Unlike SSBNs, which are designed for strategic deterrence, attack submarines -Ship Submersible Nuclear (SSNs) are tasked with hunting enemy vessels and protecting naval assets.

The SSBN fleet is expected to operate from the high-security Project Varsha facility near Visakhapatnam, which features underground pens designed to shield nuclear submarines from surveillance and potential strikes. Its location offers direct access to the Bay of Bengal and the wider Indian Ocean.

India’s nuclear assets are managed by the Strategic Forces Command (SFC), with the sea-based leg considered the most survivable component of the triad due to the stealth and mobility of submarines.

With Aridaman’s induction, India joins a select group of nations, including the United States, Russia, the United Kingdom and China, that operate a full-fledged nuclear triad backed by nuclear-powered submarines. Officials say the expansion will enhance deterrence stability and provide greater strategic assurance in an increasingly contested maritime environment.

Ravi Shankar