U.K. Royal Navy Unveils First Uncrewed Submarine ‘Excalibur’

The U.K. Royal Navy has unveiled Excalibur, its first and largest Extra-Large Uncrewed Underwater Vessel (XLUUV) tested to date.

Formally presented at HM Naval Base Devonport, the 12-metre-long, 19-tonne vessel—built under Project Cetus—was revealed in front of 200 guests, including Rear Admiral James Parkin, representatives from AUKUS nations, naval trainees, and cadets.

The unveiling is the result of a three-year project led by Plymouth-based firm MSubs, which specialises in autonomous submersibles.

Over the next two years, Excalibur will carry out extensive sea trials to explore how the U.K. can integrate large uncrewed vessels into its future maritime operations. It will not conduct operational duties but instead act as a demonstrator platform for technology testing, concept development, and payload experimentation.

Operating under the Royal Navy’s Disruptive Capabilities and Technologies Office, Excalibur will be part of the newly created Fleet Experimentation Squadron alongside surface ship XV Patrick Blackett.

The XLUUV will contribute to the Royal Navy’s intelligence-gathering and surveillance capabilities and will help explore how to safeguard critical underwater infrastructure, support allied naval assets, and deter potential underwater threats.