As of early 2026, India’s strategic posture has undergone a seismic shift, moving from a land-centric nuclear deterrent to a robust and survivable sea-based triad. The commissioning of its latest Ship Submersible Ballistic Nuclear (SSBN) missile submarines marks the culmination of the decades-old Advanced Technology Vessel (ATV) project. This secretive program has matured into a credible second-strike capability, anchoring India’s “No First Use” (NFU) policy. However, as India solidifies its silent sentinels, it faces an increasingly formidable People’s Liberation Army Navy (PLAN), which is simultaneously expanding its reach and technological sophistication in the Indo-Pacific.
India’s SSBN journey began with the INS Arihant, commissioned in 2016. While initially viewed as a technology demonstrator, its 2018 completion of a first deterrence patrol proved that India could successfully miniaturise an 83 MW pressurised water reactor and integrate vertical launch tubes for nuclear-tipped missiles. The fleet has since evolved rapidly. The INS Arihant was primarily limited by the K-15 Sagarika missile, with a range of 750 km. This was followed by the INS Arighaat, commissioned in August 2024, which featured upgraded sensors and operationalised the K-4 SLBM, extending India’s reach to 3,500 km.
India’s SSBN Journey
The upcoming commissioning of the INS Aridhaman (S4) in April–May 2026 represents a significant leap in firepower. As a “stretched” variant displacing nearly 7,000 tonnes, it features eight missile tubes—double that of its predecessors—allowing it to carry eight K-4s or up to 24 K-15s. Furthermore, the fourth vessel, INS Arisudan (S4), began sea trials in December 2025 and is slated for induction in 2027. This growth is supported by the K-series missile program, where the K-4 serves as the current backbone, while the K-5 and K-6 are in development for the future 14,000-tonne S5-class submarines, which will provide intercontinental reach.
The “Make in India” initiative has fundamentally transformed the SSBN program from a secretive research project into a cornerstone of indigenous industrial pride, with the latest vessels boasting an indigenous content level exceeding 75 per cent. This self-reliance is anchored in the domestic production of DMR-249 specialised steel by the Steel Authority of India (SAIL), which ended the nation’s reliance on imported hull materials.
By mid-2026, with three operational SSBNs, India will achieve Continuous At-Sea Deterrence (CASD), ensuring that its nuclear response remains immune to a decapitating first strike
Private sector titans like Larsen & Toubro (L&T) have pioneered modular construction techniques, while the Defence Research and Development Organisation (DRDO) has developed proprietary sonar suites, communication systems, and the critical K-series missile silos. By fostering a sophisticated ecosystem of over 100 Indian MSMEs, the program has successfully insulated India’s strategic second-strike capability from foreign supply chain disruptions and international sanctions regimes, ensuring that the core of its nuclear triad remains a truly sovereign asset.
India’s SSBN Synergy with France and Germany
While India’s SSBN programme remains a strictly indigenous “black project” to protect its strategic sovereignty, its success is analytically inseparable from the deep-rooted technical ecosystems fostered through cooperation with France and Germany. France, through Naval Group, has provided the industrial blueprint for India’s modern submarine manufacturing at Mazagon Dock Shipbuilders (MDL), delivering six Scorpène-class (Kalvari) boats by early 2025. This collaboration matured into a “Special Global Strategic Partnership” in February 2026, with France increasingly viewed as the primary Western candidate for potential consultancy on India’s future nuclear-powered attack submarines (SSNs). SSN stands for Ship Submersible Nuclear, the NATO hull classification symbol for a nuclear-powered attack submarine (where “SS” denotes submarine and “N” denotes nuclear propulsion).
Simultaneously, Germany has emerged as a critical pillar of India’s conventional “bastion” defence. In early 2026, German Chancellor Friedrich Merz finalised a landmark $8–10 billion deal for six Type-214 next-generation submarines under Project-75I. By integrating high-end German Air-Independent Propulsion (AIP) technology and French-origin manufacturing expertise, India is effectively insulating its SSBN fleet within a “protected zone” of advanced conventional assets, allowing its nuclear-armed vessels to maintain stealth while deterring the growing presence of China’s People’s Liberation Army Navy (PLAN) in the Indian Ocean.
Comparison vis-à-vis the PLAN
When compared to the PLAN, India still faces a substantial quantitative and qualitative gap. China currently operates between six and seven Type 094/094A Jin-class SSBNs, armed with the JL-3 missile, which boasts a range exceeding 10,000 km. This allows Chinese boats to strike deep into distant continents from the relative safety of the South China Sea. In contrast, India is only now approaching similar stand-off capabilities. While China’s earlier boats were noted for being noisy, their next-generation Type 096 Tang-class is expected to feature acoustic dampening that rivals world-class stealth standards.
The transition to the 14,000-tonne S5-class represents the next frontier, offering an opportunity to project power far beyond regional waters while anchoring India’s strategic sovereignty firmly beneath the waves
The strategic disparity extends to the broader naval fleet. China possesses over 70 submarines and employs a “bastion” strategy supported by a massive fleet of destroyers. India is countering this by recently issuing an RFI for submarine-launched cruise missiles and approving the construction of indigenous SSNs to hunt enemy vessels. By mid-2026, with three operational SSBNs, India will achieve Continuous At-Sea Deterrence (CASD). While the Chinese fleet remains larger, India’s focus on the home-field advantage of the Indian Ocean ensures that the Strategic Forces Command maintains a survivable and devastating response capability.
Assessment of India’s SSBN
The assessment of the SSBN project reveals a narrative of extreme technical endurance overcoming decades of geopolitical isolation. The primary challenge resided in the miniaturisation of a nuclear reactor to fit the confined hull of a submarine—a feat achieved through the Advanced Technology Vessel (ATV) project only after persistent failures in shielding and cooling systems. Historically, India lacked a domestic industrial base for high-grade submarine steel and specialised sensors, forcing reliance on secretive Russian design consultancy that often clashed with indigenous requirements. Furthermore, the missile-platform gap posed a strategic hurdle; for years, the INS Arihant was operational but lacked a long-range weapon, effectively serving as a short-reach deterrent that required the boat to venture into high-risk enemy waters to strike targets.
However, these challenges have birthed significant opportunities, transforming India from a technology importer into a self-reliant maritime power. The program has successfully fostered an indigenous military-industrial complex, involving over 100 Indian MSMEs and major firms like L&T, which now possess the expertise to build modular submarine sections. This maturation allows India to bypass the restrictive Missile Technology Control Regime (MTCR) by developing its own K-series SLBMs, such as the K-4 and K-5. The current opportunity lies in achieving CASD by late 2026, ensuring that India’s nuclear response remains immune to a decapitating first strike—a capability that commands a unique level of respect even from the numerically superior Chinese PLAN.
Ultimately, the SSBN project’s greatest achievement is its role as a stabiliser in the Indo-Pacific. While the Chinese naval fleet continues its rapid expansion, India’s program provides a silent counter-balance that does not rely on massive hull counts but on the absolute certainty of a second strike. The transition to the 14,000-tonne S5-class represents the next frontier, offering an opportunity to project power far beyond regional waters. Despite the immense capital costs and the engineering difficulty of masking acoustic signatures, the project remains India’s most successful black program, ensuring that the nation’s strategic sovereignty is anchored firmly beneath the waves.
–The writer is Assistant Professor, ICFAI School of Liberal Arts, ICFAI University, Jaipur. The views expressed are of the writer and do not necessarily reflect the views of Raksha Anirveda
