China is rapidly advancing its uncrewed submarine capabilities, testing two massive new drones, estimated to be over 40 meters long, in the South China Sea. Far larger than Western XLUUVs like the US Navy’s Orca, these submarines signal a potential new class (dubbed “XXLUUVs”) with the size and payload capacity of crewed submarines, according to Naval News. Stored in floating docks for secrecy and easier deployment, these drones may carry advanced sensors, AI systems, and substantial weaponry. Their development marks a significant leap ahead of the West in underwater drone warfare, challenging assumptions about China’s technological lag and reshaping future naval strategy. They write:
In the West, defence firms are rushing to build extra-large underwater vehicles. Navies are testing them and starting to explore how they bring new capabilities, and operate alongside other naval vessels. Meanwhile, China is years ahead in terms of both investment and ambition.
China is testing new underwater drones which literally and figuratively dwarf even the largest Western designs. At over 40 meters long they make the U.S. Navy’s Orca XLUUV (extra-large uncrewed underwater vehicle) look like a bath toy. […]
From the manner in which they are being housed and deployed it is now clear that they are indeed uncrewed platforms. The current term used for larger underwater drones, XLUUV, doesn’t do these new vessels justice however. It was never future-proof to use ‘XL’ (Extra Large) in a designation since it was inevitable that people would soon build much larger ones. These latest types are about 10-20 times larger than what passes for an XLUUV in Europe. So possibly XXLUUV or Ultra-Large-UUV? […]
BREAKING: China has officially unveiled its new unmanned underwater vehicles, HSU-100 and AJX-002 Advanced naval drones for reconnaissance and strategic missions — similar in concept to Russia’s Poseidon, a long-range nuclear-capable torpedo designed for strategic… pic.twitter.com/EHGUKcXvB7
— Defence Index (@Defence_Index) September 3, 2025
It has long been a working assumption that Chinese naval technology is decades behind the West. And that Chinese engineers are not inclined to innovate. These attitudes have been shown to be outdated, yet they persist. These new XXLUUVs are thus yet another wake up call for Western planners.
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