UK tests giant submarine drone piloted remotely from 10,000 miles away

The UK’s Royal Navy has remotely piloted its new 40-foot submarine drone, Excalibur, from the other side of the world in a test under the AUKUS security partnership.

During July’s Exercise Talisman Sabre, operators in Australia controlled the vessel while it was submerged more than 10,000 miles away at its base in Plymouth, marking the first demonstration of UK-Australia interoperability with extra-large uncrewed underwater vehicles (XLUUVs), Caliber.Az reports, referring to foreign media outlets.

Excalibur, unveiled in May and built under the three-year Project Cetus by Plymouth-based MSubs, is the Royal Navy’s first XLUUV. Measuring 12 meters long and weighing 21 tons, it can travel 1,000 miles and dive deeper than crewed submarines. Officials say it is not a combat weapon but a testbed for integrating uncrewed systems into naval operations.

The trial was part of the AUKUS Pillar II “Maritime Big Play” program, which explores the use of autonomous and robotic systems at sea. The UK, US, and Australia also coordinated with Japan to improve underwater acoustic communications.

Rear Admiral James Parkin, the Royal Navy’s Director of Developments, called the milestone “an exciting day,” stressing that Excalibur will help prepare the fleet for an era of autonomy. Commodore Marcus Rose added that the upcoming trials would accelerate understanding of large uncrewed platforms, building on experience from mine-hunting programs.

Excalibur has already completed harbour and sea acceptance trials and will undergo two years of testing with the Royal Navy’s Fleet Experimentation Squadron. Its modular design allows payload customisation for surveillance and reconnaissance missions.

The name Excalibur draws on both the legend of King Arthur and a Cold War experimental submarine, underscoring heritage and innovation. With the program, the Royal Navy joins the US and Australia, which are developing the Orca and Ghost Shark XLUUVs, in advancing undersea autonomy as major powers expand their underwater capabilities.

By Tamilla Hasanova