The Royal Navy has successfully carried out a historic trial of its new Extra-Large Uncrewed Underwater Vehicle (XLUUV), Excalibur, during Exercise Talisman Sabre. In a first-of-its-kind demonstration under the AUKUS Pillar II framework, the submarine drone was remotely controlled from Australia while submerged in UK waters—more than 10,000 miles away—highlighting a revolutionary leap in autonomous undersea warfare.
Built by MSubs in Plymouth under Project Cetus, Excalibur is a 12-meter-long autonomous submarine capable of operating for more than 30 days underwater with a range exceeding 3,000 nautical miles. Its modular payload bay allows it to be quickly reconfigured for multiple missions, including intelligence gathering, mine countermeasures, seabed warfare, and underwater electronic operations. Equipped with AI-driven mission control, secure satellite and acoustic communications, and a stealth-optimized hull powered by advanced lithium-ion batteries, Excalibur is designed to operate undetected in contested waters.
Excalibur’s integration into AUKUS symbolizes a shift from traditional defense cooperation to a digitally integrated force model. The trial showcased not only secure cross-continental command and communication but also shared operational planning, enabling AUKUS members to function as a unified underwater network across the Indo-Pacific.
Tactically, Excalibur acts as a force multiplier—able to scout ahead of crewed submarines, deploy sensors, or perform deception operations. Its stealth endurance makes it ideal for high-risk environments such as the South China Sea or the GIUK gap, while its modular systems allow for potential future roles, including precision strike.
With global interest in XLUUVs rising, Excalibur highlights the cost-effective and survivable future of undersea warfare. Its operational success strengthens the UK’s strategic posture both in the Indo-Pacific and the North Atlantic, reaffirming its commitment to allied security against growing Russian and Chinese maritime power.
By proving Excalibur in real-world conditions, the Royal Navy has positioned itself as a pioneer in autonomous submarine warfare, signaling a new era of allied dominance beneath the waves.
