India maintains a calculated and deliberate approach to its undersea deterrent, operating a modest yet technologically significant fleet of nuclear submarines. This inventory is designed to ensure a credible second-strike capability, forming a crucial leg of the nation’s nuclear triad while projecting regional maritime security. The precise count and capabilities of these vessels are often misunderstood, obscured by classification and strategic ambiguity.
Current Inventory of Active Nuclear Submarines
As of 2024, India operates a total of five nuclear-powered submarines, split between two distinct classes with different strategic roles. This number includes both the ballistic missile submarines (SSBNs) tasked with nuclear deterrence and the attack submarines (SSNs) focused on anti-shipping and intelligence gathering. The fleet is small but represents a massive investment in complex engineering and maritime doctrine for a nation that primarily focuses on regional defense.
Arihant Class: The Indigenous Deterrent
The Arihant class forms the core of India’s nuclear sea-based deterrent, comprising India’s first domestically built nuclear submarines. These vessels displace around 6,000 tonnes and are equipped with K-15 Sagarika ballistic missiles, giving them the ability to strike land targets within regional confines. With a reported complement of four submarines planned, the current operational tally includes the INS Arihant, INS Arighat, and INS S4, establishing a foundational second-strike capability born from indigenous ambition.
Chakra Class: Advanced Russian Attack Submarines
To augment the indigenous efforts, India leases advanced nuclear attack submarines from Russia, known as the Akula-class or Project 971 Chakra. These are far larger and more capable hunter-killer vessels compared to the Arihant class, designed to dominate the underwater battlespace. The current operational submarine is the INS Chakra, a leased vessel that significantly enhances India’s ability to track and neutralize adversary shipping and surface combatants in contested waters.
The Strategic Rationale Behind a Small Fleet
The limited number of submarines India operates is a function of immense technical difficulty and fiscal pragmatism. Unlike larger maritime powers that prioritize volume, Indian naval strategy emphasizes quality, survivability, and the invulnerable second-strike posture that nuclear submarines provide. Each vessel represents years of development and billions of dollars, making the expansion of this fleet a slow, deliberate process rather than an arms race response.
Project 75I and the Pursuit of Conventional Supremacy
While the nuclear deterrent receives the most attention, India is also heavily investing in conventional submarine warfare through the Project 75I class. These modern diesel-electric submarines, equipped with air-independent propulsion (AIP) and advanced weaponry, are not nuclear but are critical for regional dominance. The focus on these conventional boats allows the nuclear fleet to remain concentrated on the singular mission of nuclear deterrence, separating strategic roles from tactical maritime control.
Future Trajectory and the S5 Program
Looking ahead, India is actively working to increase the size and sophistication of its undersea fleet to meet growing strategic challenges. The next major milestone is the induction of the S5 class submarines, which will be significantly larger than the Arihant class and capable of firing longer-range missiles. These vessels, coupled with the continued leasing of Chakra-class submarines, signal a shift toward a larger and more powerful underwater force capable of securing sea lines of communication far beyond the Indian Ocean region.
