China Sets World Record With 116-Drone Autonomous Underwater Swarm

Guinness World Records has officially recognized a Chinese test involving 116 autonomous underwater drones as the largest such swarm in history. Researchers at Northwestern Polytechnical University deployed 116 TH-618 submersibles in a pool measuring 164 feet by 65 feet, where the vehicles executed formations and maneuvers without human intervention. The August 2026 trial has direct ties to China's military pipeline, and it lands at a moment when navies worldwide are racing to field cheap, disposable unmanned systems.

The record matters because of who ran it. The US government has designated Northwestern Polytechnical University as a developer of technologies for the People's Liberation Army. The university conducted the experiment together with Xi'an Tianhe Maritime Technologies, a subsidiary of defense contractor Xian Tianhe Defense Technology.

According to the South China Morning Post, the university said that developing submersible drone swarms "has always been a core challenge in the global field of underwater intelligent equipment. This time, the stable navigation of a cluster of hundreds of vehicles represents a breakthrough in the large-scale coordinated navigation of underwater unmanned systems."

What did the drones actually do?

Each TH-618 resembles a long pipe fitted with four propellers and a camera. The vehicles are roughly 2 feet long, half a foot wide and weigh 11 pounds. They have a range of just over 18 miles and can operate continuously for about 8 hours.

The drones navigate using smartphone cameras attached to their fronts, allowing AI systems to adjust routes in real time in response to underwater disturbances and collisions. The university says the drones can autonomously conduct complex maneuvers, including:

• terrain tracking
• landmark recognition
• vertical lift
• depth and speed control
• hovering in water, using multi-degree-of-freedom thrusters

During the record attempt, the swarm relied solely on visual data. Over roughly 34 minutes, the drones navigated around the pool autonomously and covered more than 1,600 feet without human intervention.

The experiment is the culmination of over two decades of research. In creating a miniaturized submersible capable of coordinating autonomous responses to environmental stimuli, the Northwestern Polytechnical University team may have taken a step toward a new era of subsurface research, intelligence gathering and warfare.

Why is underwater swarm navigation so hard?

Underwater drone navigation is far more complex than its aerial counterpart. Developers cannot use wireless communications or satellite positioning and navigation systems for course calibration beneath the surface. Low visibility and high water pressure complicate subsurface coordination further.

Drones must instead rely on a combination of underwater sensing, subsurface target detection and acoustic communication to respond autonomously to an irregular operating environment. Coordinating those efforts across a swarm of 116 vehicles is a separate challenge altogether, which is what makes the record significant as a research result, not just a publicity mark.

The pool setting remains a limitation. A controlled test environment is a poor stand-in for open ocean, and the technology has a long way to go before it transforms China's naval operations. Still, the test indicates the direction of China's subsurface and drone development programs.

How does this fit China's naval strategy?

The PLA Navy is currently the world's largest navy by vessel count, built largely around smaller, nimble ships designed to patrol the contested littoral waters of the South China Sea. China has commissioned three aircraft carriers in the last decade and a half, but its fleet still lags behind the United States in total firepower. Some analysts believe drones could close that gap and enable the PLA's expanding naval ambitions. Others worry that proliferating drones will lower the threshold for naval engagements at a time when naval intelligence already faces uncertainty.

China has invested heavily in subsurface vessels and research, and the investment is dual-purpose. It could boost the country's deep-sea mining and subsurface infrastructure efforts while enhancing its naval buildup and intelligence gathering. Both carry geopolitical consequences given China's military and economic ambitions.

Researchers at Xi'an Tianhe Maritime Technologies highlighted the potential for coordinated swarms to monitor aquatic infrastructure and conduct research, such as inspecting gas pipelines or mapping the ocean floor. The same subsurface patrol capability could also lay the groundwork for submarine operations and defenses.

The pattern extends beyond this one test. In March 2026, researchers at CNN, the Pulitzer Center and environmental outlet Mongabay reported that China had spent years surveying the maritime environments of strategically critical waterways. Beijing billed the effort as exploration for deep-sea mining and oceanographic research, but it extended well beyond China's mining exploration rights and focused on key naval and economic shipping routes. Western military experts warned that the project likely boosted China's subsurface intelligence operations.

What is the 'Transparent Ocean' plan?

For the PLA Navy, these swarms are likely one component of a seabed-to-space defense architecture known as the Transparent Ocean. In July 2026, two PLA-affiliated research institutions published a proposal for teams of drones to patrol the contested waters of the South China Sea. The robotic "fortress" would see China patrolling its geopolitical neighborhood with swarms of aerial, surface and submarine drones.

The PLAN has already made measurable progress toward these goals. China is the first country to develop full-size uncrewed submarines. It is also reportedly developing at least two submersible motherships designed to launch uncrewed subs and drone carriers across its aerial, surface and subsurface fleet.

Who else is in the race?

China is not alone. During the Russia-Ukraine war, a previously inactive Ukrainian Navy destroyed one third of Russia's fleet using masses of aerial, surface and submarine drones. Global powers are now racing to add these asymmetric weapons to their own fleets.

Drones present a distinct opportunity for countries without traditional naval capabilities. They are extremely cheap and easy to build, and militaries are learning to overwhelm opponents with disposable attack vehicles. Thwarting such assaults is difficult, especially when defensive missiles cost millions more than their targets. AI-coordinated drone swarms also pose an acute threat to aircraft carriers.

The pace of firsts is accelerating. In December 2025, Ukraine carried out the first successful subsurface drone strike against an enemy submarine, hitting a Russian submarine in Novorossiysk. The attack forced Russia to begin deploying anti-drone nets across its submarine fleet.

Traditional naval powers have moved as well. Researchers from Poland, Germany, Portugal and Slovenia have made strides toward launching autonomous subsurface drone swarms through the European Defence Agency's Swarm of Biomimetic Underwater Vehicles project. The US military acknowledged the danger drones pose to its nuclear submarine fleet when it issued an open call for submarine drone defense systems in July 2026. A few months later, the US Navy launched its first unmanned surface vessel alongside a carrier strike group.

China may nonetheless hold an edge over its rivals. As the world's leading manufacturer of both drone components and ships, its dual-purpose shipbuilding industrial complex suits this type of military buildup well, and tariffs will not alter that structural advantage. Whether the PLA can move a 116-drone swarm from a test pool to the South China Sea will shape the next phase of the naval drone race.