India's Unmanned Underwater Vehicles: Enhancing Sea Denial Capabilities

India's Unmanned Underwater Vehicles: Enhancing Sea Denial Capabilities

India's maritime security landscape is evolving, with the Indian Navy's XLUUV programme gaining momentum. The programme aims to develop 100-tonne-class unmanned underwater vehicles (XLUUVs) to enhance sea denial capabilities. These vehicles will conduct surveillance, deploy mines, and deliver payloads without exposing crew to risk.

The Indian Navy's XLUUVs will play a crucial role in addressing the country's two-front maritime contingency. The Indian Ocean is vast, and the Navy's submarine numbers remain limited. The People's Liberation Army Navy (PLAN) is expanding its underwater and unmanned capabilities, making it essential for India to develop its own XLUUVs.

XLUUVs offer a means of adding persistent underwater presence without exposing a submarine's crew to risk. They can conduct surveillance, deploy mines, or position a payload in an area where an adversary is expected to pass. This concept is particularly applicable to sea-denial operations, where an unmanned underwater vehicle need not pursue a fast warship.

The Navy's XLUUV programme is well beyond the conceptual phase, with an approved budget of roughly 2,500 crore for about 100-tonne-class unmanned underwater vehicles under the Make-I route in the 2024 fiscal year. The intended platforms for the programme would be for surveillance missions, mine warfare, and the delivery of weapons against surface ships and submarines.

Open-source reports have placed the planned 12 XLUUVs, although the government's public Make-I listing does not itself specify the number. India is also developing the High Endurance Autonomous Underwater Vehicle (HEAUV) through DRDO's Naval Science and Technological Laboratory (NSTL), with Cochin Shipyard Limited as a development partner. The six-tonne HEAUV is about 10 metres in length and is designed to endure 15 days at three knots, with a maximum speed of about eight knots.

Prototype trials have already demonstrated surface and submerged operations, including sonar and communications performance. China's September 2025 military parade provided a glimpse of how quickly the technology is developing. Beijing unveiled five AJX002 unmanned underwater vehicles and three HSU100s, while larger uncrewed submarine designs have also been seen undergoing trials.

The United States is pursuing a similar concept to that of China's. Its Orca XLUUV programme initially focused on covert payload delivery and mine warfare, while the emerging Liberator system is designed as a seabed launcher for heavyweight torpedoes. For India, the near-term value of XLUUVs would therefore lie in surveillance, mine warfare, seabed payloads, and selective ambush operations, rather than autonomous underwater vehicles conducting conventional torpedo chases.

India's geography provides potential areas in which such systems could potentially contribute to sea denial, including approaches around the Andaman Sea and important Indian Ocean shipping routes. However, endurance remains a fundamental limitation, while underwater communications and autonomous weapons employment present challenging technical and doctrinal issues.

The development of XLUUVs is a significant step towards enhancing India's undersea warfare capabilities. As the technology continues to evolve, it is essential for India to address the challenges associated with XLUUVs and ensure their effective integration into the Navy's operational plans. The future of XLUUVs holds great promise for India's maritime security, and it is crucial to harness this potential to ensure the country's continued security and prosperity.