The newly Launched S4 Boasts about 75 Per cent Indigenous Parts and is Equipped with K-4 Nuclear Ballistic Missiles, Capable of Hitting Targets up to 3,500 km Away

India has launched its fourth nuclear-powered ballistic missile submarine (SSBN).

Codenamed S4, the submarine was launched on 16 October at the Ship-Building Centre (SBC) after Defence Minister Rajnath Singh inaugurated a Very Low Frequency Naval Station.

The launch is part of India's efforts to strengthen its nuclear deterrence capabilities and comes amid ongoing diplomatic tensions with Canada.

The newly launched S4 boasts about 75 per cent indigenous parts and is equipped with K-4 nuclear ballistic missiles, capable of hitting targets up to 3,500 km away.

It is a significant upgrade from the earlier INS Arihant, which carries K-15 missiles with a range of 750 km.

The submarine is part of a growing SSBN fleet and plays a crucial role in India's sea-based nuclear deterrence strategy.

The submarines boast a virtually unlimited range and endurance, allowing for extended patrols with only food, crew fatigue, and maintenance limiting their endurance.

The launch of S4 follows the commissioning of INS Arighaat in August 2024 and the INS Aridhaman is set for commissioning next year.

Both INS Arihant and INS Arighaat are already on deep sea patrols.

Additionally, a leased Russian Akula-class nuclear-powered attack submarine is expected to join the fleet in 2028.

India's SSBN fleet operates in deep-sea patrols, adding to the country's strategic defence in the Indo-Pacific region.

In addition to SSBNs, the Indian government has approved the construction of more nuclear-powered attack submarines, with plans to build two more as part of its efforts to counter challenges in the region.
The Indian government, as per reports, has shifted its focus towards submarine-based deterrence over aircraft carriers, largely due to concerns that carriers are vulnerable to long-range missiles, particularly from China.

This emphasis on strengthening submarine power comes as China increases its naval presence in the Indian Ocean, with 10-11 ships operating in the region monthly since last year.