India’s Project-76 submarine program represents a decisive leap in indigenous naval capability, aiming to deliver twelve advanced diesel-electric attack submarines with Air Independent Propulsion and lithium-ion batteries by the mid-2030s.
The initiative is designed to replace the ageing Kilo-class fleet while achieving unprecedented levels of indigenisation and endurance.
India’s Project-76 initiative is structured around the induction of twelve submarines, each weighing approximately 3,000 tonnes, to replace the ageing Sindhughosh-class units. The Warship Design Bureau and the Defence Research and Development Organisation are leading the design phase, with indigenous content projected between 70 and 80 percent.
This marks a significant departure from earlier reliance on foreign OEMs, reflecting the Aatmanirbhar Bharat philosophy of sovereign capability in undersea warfare. Technical and preliminary designs are actively underway, with production orders expected around 2028 and the first inductions beginning by 2034.
The program is strategically designed to split construction between Mazagon Dock Shipbuilders Limited and Larsen & Toubro, enabling parallel production lines to compress delivery timelines. Each shipyard is expected to deliver six submarines, ensuring steady induction into the fleet.
The propulsion architecture is particularly innovative, combining India’s indigenous fuel-cell based AIP system with high-capacity lithium-ion batteries. This hybrid endurance concept allows for extremely quiet patrols lasting weeks without surfacing, while lithium-ion batteries provide rapid bursts of power for manoeuvres and combat.
Compared with traditional lead-acid systems, lithium-ion batteries offer faster recharge, higher energy density, and sustained performance under heavy loads.
Sea trials of the indigenous AIP module are scheduled aboard INS Khanderi later in 2026, serving as a real-world demonstrator for Project-76 technologies. Successful validation will pave the way for integration into the new submarines.
The endurance profile envisaged allows the boats to remain submerged for more than twenty days during low-speed patrols, a capability particularly valuable in the vast Indian Ocean Region where stealth and persistence are critical. Armament is expected to include heavyweight torpedoes and land-attack cruise missiles, giving the submarines both defensive and offensive reach.
The strategic context of Project-76 is closely tied to India’s broader underwater modernisation roadmap. Alongside Project-75I, which involves German-designed AIP submarines, and Project-77, which will deliver nuclear-powered attack submarines, Project-76 is intended to bridge operational gaps and ensure balanced fleet capability.
The program also aligns with the long-term Submarine Building Perspective Plan approved by the Cabinet Committee on Security, which envisaged twenty-four submarines over three decades. Project-76 represents the second phase of this plan, focused entirely on indigenous design and construction.
Financially, the program is estimated at around ₹70,000 crore, making it one of India’s largest defence investments. Risks include potential delays in design finalisation, technology integration challenges, and the need to synchronise production across multiple shipyards.
However, the emphasis on indigenous intellectual property and reduced foreign dependency is expected to yield long-term strategic dividends. The submarines will not only replace ageing assets but also enhance deterrence against expanding Chinese and Pakistani undersea capabilities in the Indo-Pacific.
In essence, Project-76 is a cornerstone of India’s naval modernisation, combining indigenous propulsion breakthroughs with parallel shipyard production to deliver twelve advanced submarines by the mid-2030s.
It reflects a decisive push towards self-reliance, endurance, and stealth in undersea warfare, ensuring the Indian Navy remains a formidable force in the Indian Ocean Region.
Agencies
