Can the West keep up with China’s “XXL” uncrewed submarines?
The Royal Navy unveiled Excalibur in May 2025 at HMNB Davenport. (Photo: Crown Copyright)
The UK, the US and Australia have all been working on “extra-large” uncrewed underwater vehicles, but China’s reported development of a significantly larger capability demonstrates the country’s rapid advancement in underwater warfare.
As global militaries continue to focus on advancing autonomous and uncrewed capabilities to tackle emerging threats, multiple navies made significant progress in 2025 on their uncrewed submarine developments – and notably on extra-large uncrewed underwater vehicles (XLUUVs).
While conventional submarines remain crucial to contemporary fleets, autonomous, crewless platforms aim to work alongside traditional vessels to enhance the functions of the force; in much the same way as uncrewed capabilities are increasingly becoming crucial to air and land exercises.
With uses ranging from intelligence, surveillance and reconnaissance (ISR), anti-submarine warfare (ASW), mine-laying and mine countermeasures and payload delivery, XLUUVs can operate in challenging or dangerous
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