Giant Chinese drone subs to punch holes in US seabed surveillance

AllAfrica

a day ago

China is preparing to put its undersea ambitions on parade, rolling out giant drone submarines that could one day strike at the US undersea sensor network and tilt the balance of the Pacific's silent war.
This month, Naval News reported that China is expected to unveil two new extra-large uncrewed underwater vehicles (XLUUVs) during a September 3 military parade in Beijing marking the 80th anniversary of the end of the Second Sino-Japanese War.
The unveiling will be the first public appearance of these unmanned assets and will seek to signal China's rapid progress in underwater drone technology.
The AJX002 model, approximately 18–20 meters long with pump-jet propulsion and modular transport features, has been observed uncovered during parade rehearsals. A second, larger design—concealed under tarpaulin—features dual stern masts and X-form rudders, suggesting significant design divergence.
The Chinese Ministry of National Defense has stated the parade will showcase 'improved weapons, equipment,' underscoring an intent to lead in underwater warfare capabilities.
With at least six XLUUVs rehearsed for display, analysts anticipate a clearer read on China's operational priorities and technological maturity once the vehicles roll past Tiananmen.
If war comes, XLUUVs are the logical tools to go after the US-led undersea surveillance grid that hems in the People's Liberation Army Navy (PLAN) and constrains its freedom of action beyond the First Island Chain.
Desmond Ball and Richard Tanter note in their 2015 book 'The Tools of Owatatsumi: Japan's Ocean Surveillance and Coastal Defense Capabilities' that by the mid-2000s US undersea surveillance in the western Pacific was centered on the Fish Hook Undersea Defense Line, a modern chain of fixed arrays to monitor Chinese submarines transiting between the East and South China Seas and the Pacific.
Ball and Tanter write that the line arcs from Kyushu's Kagoshima down the Osumi Islands to Okinawa, then via Miyako and Yonaguni past Taiwan to the Philippines' Balabac, onward to Lombok in eastern Indonesia and across the Sunda Strait to northern Sumatra and the Andamans with key nodes at Okinawa and Guam and allied sections provided by Japan and Taiwan.
The Fish Hook's purpose is not subtle, and Beijing knows it. Underscoring the threat the network poses to China's submarine force, Ryan Martinson writes in a June 2025 Center for International Maritime Security article that even with rapid modernization, China's submarine fleet remains critically vulnerable to US undersea surveillance.
Citing People's Liberation Army Navy officers in the Military Art journal, Martinson says Chinese submarines face a 'fairly high probability' of detection during peacetime operations, even within the First Island Chain.
He says the US Navy's integrated surveillance system—spanning seabed sensors, satellites, aircraft and unmanned vehicles—can track PLAN submarines from port to patrol. Martinson notes this persistent exposure compromises stealth, submarine warfare's core advantage, and raises doubts about operational viability.
XLUUVs offer a way to take the sensors' eyes and ears offline. To degrade these formidable capabilities, David Axe notes in a July 2025 article for The Strategist that China is exploring means to disable the US undersea sensor network, including deploying remotely operated vehicles to sever cables, autonomous submarines to plant explosives and long-range underwater drones capable of delayed activation via acoustic signals.
Axe notes that these tactics, both overt and covert, aim to neutralize a critical US advantage in seabed surveillance. Were such capabilities fielded at scale, the effect would not be theatrical sabotage but a methodical campaign to blind fixed arrays, snarl repair timelines and force the US and its allies to rely on more expensive, finite and predictable patrol patterns.
The stakes for China's broader war plans are straightforward. Should China manage to neutralize US and allied undersea sensor networks, its submarines could contribute substantially to a blockade of Taiwan, and its undersea nuclear deterrent would be freed from the constraints of a bastion strategy in the South China Sea.
In an August 2024 report for the Center for Strategic and International Studies (CSIS), Bonny Lin and others note that Chinese submarines are poised to play a critical role in enforcing a blockade of Taiwan.
Lin and others say that in high-intensity operations, PLAN submarines would conduct covert mine-laying near Taiwan's ports and shipping lanes, disrupt maritime traffic and support joint firepower strikes.
The writers add that stealth enables early deployment to shape the battlespace, while integration with aviation units enhances interdiction. They add that submarines bolster China's ability to maintain persistent pressure, complicate Taiwan's maritime awareness and deter foreign intervention.
Neutralizing the Fish Hook would have equally profound implications for China's nuclear deterrent. China is implementing a bastion strategy in the South China Sea, where its nuclear ballistic-missile submarines can operate inside a protected zone defended by artificial islands, land-based aircraft and warships.
Further, China's nuclear-powered ballistic missile submarines (SSBNs) armed with the JL-2 submarine-launched ballistic missile do not have the range to hit the US mainland from the South China Sea, although the longer-ranged JL-3 will allow it to do so.
However, in a bastion strategy, China's SSBNs remain bottled up in a small operational area, which is routinely patrolled by US nuclear-powered attack submarines (SSNs), as opposed to Pacific open-sea patrols that exponentially increase the difficulty of tracking down submarines.
XLUUVs that can harass seabed arrays, complicate acoustic baselines and strike at repair ships would be a force multiplier for any future transition from bastion patrols to broader, less predictable open-sea deterrent patrols.
None of this makes the XLUUVs a silver bullet. The US and its allies have spent decades refining anti-submarine warfare (ASW) and are unlikely to cede the initiative.
While US and allied ASW assets can intercept Chinese submarines, the large size of China's submarine force—60 submarines according to the US Department of Defense's 2024 China Military Power Report (CMPR)—and a huge production base that has outpaced the US at the industrial level make interception with overstretched US and allied ASW capabilities a formidable challenge.
Stressing the shortage of US and allied ASW assets in the Pacific, the International Institute for Strategic Studies (IISS) noted in its 2024 Asia-Pacific Regional Security Assessment that the US and its allies continue to face challenges in sustaining comprehensive maritime domain awareness, even as they expand patrols and sensor networks across the region.
The IISS notes that India and Australia have expanded joint maritime-patrol aircraft deployments, coordinated patrols and coastal radar initiatives with partners, while smaller Southeast Asian states remain reliant on outside assistance. It adds that gaps in ASW and underwater domain awareness persist despite these efforts.
Whether China can turn its growing undersea arsenal into a durable advantage depends more on surpassing US surveillance and exploiting gaps in allied ASW defenses, which are still thin across the Pacific.
Between those facts lies the real test for the drones on parade—whether they can do enough, soon enough, to blind an adversary that has spent decades learning to see under the waves.