China has unveiled its third-generation nuclear attack submarine, the Type-09V, highlighting a stark contrast with India's submarine ambitions. While Beijing advances its undersea fleet, India remains in the nascent design phase for its first indigenous SSN. This disparity underscores broader challenges in India's naval nuclear propulsion program.

India's pursuit of nuclear submarines is not a recent endeavour. The nation has leased Russian submarines since the late 1980s to gain operational experience. The Soviet Navy's Charlie-class SSGN served as INS Chakra from 1988 to 1991, providing invaluable insights into nuclear-powered operations.

A second lease followed with an Akula-class SSN, commissioned as INS Chakra-II in 2012 and decommissioned in 2021. These vessels allowed the Indian Navy to hone tactics for nuclear submarine employment. A third Akula-class boat, under a 10-year lease signed in 2019, faces delays and is now slated for delivery around 2028.

On the ballistic missile submarine front, India has achieved notable success. The Arihant-class SSBNs, born from the secretive Advanced Technology Vessel program, represent a credible sea-based deterrent. INS Arihant entered service in 2016, followed by INS Arighaat in August 2024; both are now conducting deterrent patrols.

Progress continues with INS Aridhaman, which completed sea trials in late 2025 and awaits commissioning in early 2026. A fourth Arihant-class boat began sea trials in December 2025, with induction expected by 2027. These platforms bolster India's nuclear triad.

India's S5-class submarines represent a monumental leap in the nation's nuclear deterrence posture, poised to redefine its strategic maritime capabilities. Speculation abounds that these vessels will displace between 16,500 and 17,000 tons submerged—figures rivalling the behemoths of the US Ohio class and Britain's Vanguard class—far exceeding the 13,500 tons often cited in preliminary reports.

Much like the INS Arihant, where official disclosures understated true potential, the government is likely to downplay the S5's prowess to maintain strategic ambiguity, projecting an image of measured power rather than overt dominance.

At the heart of the S5's formidable arsenal lie 16 vertical launch tubes for next-generation ballistic missiles, either the K-5 or K-6 variants. The K-5, still under development, promises a 6,500 km range with 3-4 multiple independently targetable re-entry vehicles (MIRVs), enabling precise strikes across vast theatres. 

Should the more advanced K-6 materialise, its 8,000-9,000 km reach paired with 6-8 MIRVs would extend India's nuclear umbrella to cover the entirety of China's heartland, instilling profound unease in Beijing's military planners.

This capability is not intended for lesser contingencies; deploying such firepower against Pakistan would indeed dishonour the platform's strategic gravitas. The S5 is unequivocally engineered for peer-level threats, particularly China's expanding naval reach in the Indian Ocean. Its missile suite ensures a survivable second-strike option, capable of inflicting unacceptable damage even if India faces a disarming first strike.

Yet SSBNs serve a distinct role from SSNs. Ballistic missile submarines prioritise stealth for second-strike capability in retaliation scenarios. Attack submarines, by contrast, are designed for proactive combat, including anti-submarine warfare, escort duties, and strike missions.

India's absence of indigenous SSNs creates critical gaps. The fleet lacks persistent nuclear-powered escorts for SSBNs, limiting protection in contested waters. Adversary submarines in the Indian Ocean cannot be effectively hunted without the endurance of nuclear propulsion.

Conventional diesel-electric submarines, while capable, suffer from limited underwater endurance due to battery constraints. Nuclear attack submarines offer superior speed, sustained submerged operations, and global reach—essentials for power projection.

The indigenous SSN program, designated Project-77, received Cabinet Committee on Security approval in October 2024. It authorises construction of two boats at an estimated ₹40,000 crores. The project aims to rectify longstanding deficiencies in undersea strike capabilities.

Leadership falls to the Advanced Technology Vessel headquarters in Visakhapatnam, which manages Arihant and S5 programs. The Navy's Submarine Design Group, under the Directorate of Naval Design, handles detailed engineering, with DRDO providing technical support.

The Indian Navy envisions a force of six SSNs ultimately. The first boat targets delivery in 2036-37, the second in 2038-39—an ambitious timeline given design complexities. These vessels will feature advanced sensors, stealth enhancements, and vertical launch systems.

Powering these submarines will be a step up from the Arihant-class's 83 MW reactor. Bhabha Atomic Research Centre is developing a 190-200 MWe unit, promising greater speed and endurance. Weaponry may include DRDO's hypersonic missiles and upgraded BrahMos variants.

This timeline means India's debut SSN will emerge nearly three decades after China's second-generation Shang-class entered service. China's fleet now includes multiple generations, enabling blue-water operations across the Indo-Pacific.

India's delays stem from technological hurdles, not intent. Indigenous reactor development demands precision in miniaturisation and safety. Budget constraints and integration of advanced systems further complicate progress.

Leased Russian submarines have bridged gaps but cannot substitute for owned assets. They offer training but limit doctrinal evolution and integration with indigenous weapons. Persistent delays in the third lease exacerbate interim vulnerabilities.

The Indian Ocean's growing submarine traffic—from Chinese Xia-class SSBNs to Pakistani plans—heightens urgency. India's SSBNs require SSN escorts to counter threats, particularly in chokepoints like the Malacca Strait.

Project 77's success hinges on parallel advancements. DRDO's missile integrations and private-sector involvement in hull fabrication could accelerate timelines. Mazagon Dock and Larsen & Toubro are pivotal in scaling production.

International partnerships may aid progress. Russia's technical assistance in ATV programs persists, while potential collaborations with allies like the US or France could infuse expertise. The Quad framework underscores shared maritime concerns.

Ultimately, India's SSN program is vital for strategic autonomy. It will enable persistent presence in distant theatres, deter aggression, and secure sea lines of communication. Closing the gap with China demands sustained investment and resolve.

Even on optimistic projections, parity remains distant. China continues iterating on Type-09V and beyond, integrating AI-driven autonomy and quieting technologies. India must prioritise to match this pace.

IDN (With Agency Inputs)