India’s S5 SSBN: The Submarine That Keeps Xi Jinping Up at Night

The S5 submarine is a critical step towards India’s future “blue-water” navy—allowing it to go head-to-head with the People’s Liberation Army Navy far from India’s shores.

India is working toward ensuring its dominance in South Asia and the Indian Ocean basin with its new S5-class nuclear ballistic missile submarine. This next-generation submarine is larger and more capable than the current Arihant-class submarine.

Right now, India is in the competition of its life, as it must race against both the People’s Republic of China (PRC) as well as Pakistan for dominance in their region. Therefore, the need for a sea-based nuclear deterrent is essential.

The S5 Submarine: India’s Most Important Warship Ever 

• Year Introduced: Not yet introduced (construction started late 2025)
• Number Built: 0 (1 under construction, 4 planned)
• Length: ~492 ft (150 m)
• Beam (Width): Unknown
• Displacement: 13,500 tons
• Engines: Advanced Pressurized Water Reactor (PWR) for nuclear propulsion
• Top Speed: 30+ knots (34.5 mph, 55.5 km/h)
• Range: Unlimited (nuclear-powered)
• Armaments: K-6 Submarine-Launched Ballistic Missiles (SLBMs) with MIRV capabilities; 533mm torpedo launchers (possibly for Varunastra torpedoes)
• Crew: 100–130 personnel

Four S5-class SSBNs are planned, with the first submarine of this new class laid down in the closing weeks of December. It is expected that this new class of submersible will be available to the Indian Navy by the 2030s—meaning that the S5s will be coming into service nearly 15 years after the Arihant-class nuclear-powered submarines entered service in 2016.

The S5 takes India’s significant advantages at sea and amplifies them by ensuring that the Indian Navy possesses a reliable—and undetectable—second-strike nuclear capability. More to the point, the S5 is New Delhi’s major move toward fashioning a “blue-water” navy for itself. In naval parlance, there are three types of navies: brown-water navies, good only for patrolling a country’s internal waters; green-water navies, which can operate in coastal waters; and blue-water navies, which can operate anywhere. The great powers, notably the United States, have blue-water navies. With its vast naval force, America can go wherever it pleases, whenever it wants. India aspires to be a great power. Therefore, it requires a blue-water capacity.

The S5 Is Really Aimed at China, Not Pakistan

While the new S5 submarines will be useful in deterring neighboring Pakistan, are not really about handling Pakistan at all.

At sea, Pakistan’s Navy is only a moderate threat to India’s fleet. The real headache for India at sea is China—and confronting China at sea requires India to have a blue-water naval capability that it presently lacks.

India is steadfastly committed to competing on the world stage with increasingly complex systems. The S5 represents that commitment at sea. Having a reliable sea-based nuclear deterrent, one that can project power across vast distances, is a gamechanger for New Delhi as it will increasingly be made to contend with China’s aggressiveness toward them.

By the 2030s, when these submarines are set to enter service for the Indian Navy, the present tensions between Beijing and New Delhi may be far worse. India is making the right move in building this capability. It will both solidify its position as a great power and will ensure that it can better defend itself against serious, growing threats.