India is expected to receive a leased Russian nuclear-powered attack submarine, K-391 Bratsk, in 2028 under a contract first agreed in 2019 and now formally acknowledged in Moscow.

The 36-year-old Project 971 “Shchuka-B” (NATO: Akula-class) boat is to serve with the Indian Navy for 10 years after an extensive modernisation that is reported to include vertical launch systems for cruise missiles in addition to the submarine’s existing torpedo armament.

When the intergovernmental agreement was concluded in March 2019, defence media reported a deal worth about $3 billion for a decade-long lease of an Akula-class submarine widely described as the future “INS Chakra III”. More recent reporting based on Russian sources now cites a figure closer to $2 billion, reflecting revised estimates of refurbishment and upgrade costs. Some international coverage presented this lower sum as evidence of a new contract agreed in 2025, creating confusion over whether India had signed an additional submarine deal.

New Delhi has moved to rebut that interpretation. The Indian government’s Press Information Bureau has stated that no new submarine agreement has been signed with Russia, and that references to a $2 billion lease concern the 2019 contract, whose delivery date has slipped to 2028 after delays on the Russian side. Moscow has now confirmed that K-391 Bratsk is the hull selected for India, ending several years of speculation over which Akula-class boat would be transferred.

Bratsk entered Soviet service in 1989 and left frontline duty less than a decade later. In 2003 it was sent to the North-Eastern Ship Repair Centre in Vilyuchinsk, on Russia’s Kamchatka Peninsula, but work stalled amid funding shortages and the loss of skilled personnel. In 2013 the submarine, together with sister boat K-295 Samara, was transported on the Transshelf heavy-lift vessel to the Zvezdochka shipyard in Severodvinsk for a more ambitious overhaul. By 2022 Russian reporting described further repair as impractical, before the refit was revived in the context of the Indian lease.

The current modernisation is reported to be taking place under a project designated 09718, interpreted as a customised upgrade of the Shchuka-B design for Indian requirements. The central change would be the installation of universal vertical launch systems suitable for the Indo-Russian BrahMos cruise missile, derived from Russia’s P-800 Oniks, and potentially other missile types. In their original configuration, Akula-class submarines carry eight torpedo tubes – four 533 mm and four 650 mm – for heavyweight torpedoes and, in some Russian variants, nuclear-capable Type 65 weapons. They lack dedicated vertical launch cells.

By contrast, Russia’s newer Project 885 Yasen-class attack submarines employ universal launchers able to fire Oniks, Kalibr land-attack cruise missiles and, in later variants, the hypersonic 3M22 Zircon. Adapting Bratsk to carry a similar mix would require significant structural changes to the hull and combat system, which helps to explain both the complexity of the refit and the 2028 delivery date. Defence publications have suggested that a modernised Bratsk fitted with universal launchers could, in principle, be configured to fire BrahMos, Kalibr and possibly Zircon, although no such configuration has been officially confirmed for the Indian boat.

Open-source assessments indicate that Zircon carries a relatively small 100–150 kg warhead, consistent with Russian systems designed to accept either conventional or nuclear payloads. India is a nuclear-armed state, but there is no public evidence that it has developed compact nuclear warheads for sea-launched cruise or hypersonic missiles, and neither Moscow nor New Delhi has suggested that a leased submarine would deploy such weapons. Discussion of Zircon in connection with Bratsk therefore remains focused on potential conventional strike options rather than on nuclear sharing.

BrahMos, by contrast, is already well established in India’s arsenal. The Indian Navy is expanding its stock of BrahMos missiles for surface ships and coastal batteries, with orders for more than 200 additional rounds reported in 2023, and New Delhi has begun exporting the system, notably to the Philippines, with further prospects such as Indonesia under discussion. A submarine-launched BrahMos variant deployed on Bratsk would extend that existing missile family to the undersea domain, giving the Indian Navy another delivery platform without introducing an entirely new weapon.

The lease of Bratsk also fits a longer pattern in India’s use of Russian nuclear-powered attack submarines. The Indian Navy first operated a Soviet Project 670 Skat (Charlie-class) boat, commissioned as INS Chakra from 1988 to 1991. A second INS Chakra, the Akula-class K-152 Nerpa, entered Indian service on lease in 2012. These arrangements have provided crews and engineers with experience of nuclear propulsion while India develops its own indigenous nuclear submarine programme. The arrival of a modernised Akula-class hull in the late 2020s would continue that pattern of time-limited access to Russian platforms alongside domestic projects.

Beyond fleet composition, the Bratsk arrangement interacts with United States sanctions policy. The Countering America’s Adversaries Through Sanctions Act (CAATSA), adopted in 2017, authorises US secondary sanctions on countries that undertake significant arms purchases from Russia, Iran or North Korea. India’s acquisition of the Russian S-400 air defence system has already prompted debate in Washington over whether to invoke CAATSA penalties or to grant waivers. In July 2022 the US House of Representatives voted in favour of an India-specific waiver related to the S-400 procurement, reflecting the value attached in Washington to defence cooperation with New Delhi in the Indo-Pacific.

To date, CAATSA sanctions have not been applied to India, and the Bratsk lease continues under the framework of the 2019 contract. The combination of a refurbished Russian nuclear-powered submarine, possible integration of advanced missile systems and continued Indian demand for Russian equipment may, however, remain a test case for how far US extraterritorial sanctions will be enforced against a key strategic partner.