By Jia Feimao | 2026-06-11

A U.S. unmanned surface vessel has completed its first autonomous transit of the Taiwan Strait, sailing more than 1,000 nautical miles over five days while tracking Chinese warships and photographing their activities inside Taiwan's Exclusive Economic Zone.

U.S. marine technology company Seasats announced the mission on May 27, saying the vessel was deployed and monitored from hundreds of miles away. The company said the voyage demonstrated the ability of low-cost, long-endurance autonomous platforms to conduct persistent surveillance in contested waters without putting crews at risk.

The voyage was carried out by Lightfish, an unmanned surface vessel developed by Seasats. The 12-foot-long craft uses a fiberglass hull and solar-hybrid propulsion system that allows it to remain at sea for up to six months, supporting missions ranging from ocean research to maritime security patrols, according to the company.

During the crossing, Lightfish detected multiple Chinese naval vessels that were not transmitting Automatic Identification System signals. Images captured by the vessel identified one ship as a Type 056 corvette operated by the Chinese navy, according to Seasats.

The transit comes as Beijing continues to assert sovereignty over Taiwan and has promoted claims that the Taiwan Strait falls under its jurisdiction, a position disputed by many governments that regard the waterway as international. China has not renounced the use of force to seize Taiwan.

The encounter was not the vessel's first with a Chinese warship, but the location and timing made it notable, Seasats Chief Executive Officer Mike Flanigan said.

"It's generally understood that the PLAN [People's Liberation Army Navy] aggressively projects its vessels into the sovereign waters of smaller neighbors, but the opportunity to capture and share geolocated photographic evidence of it is unique," he said.

Relieving surveillance burden

The Taiwan Strait mission was not the company's first close encounter with the Chinese navy. In June 2025, another Lightfish operating about 330 miles northwest of Guam was shadowed by the Chinese destroyer Nanchang, which at one point approached within only a few meters.

Chinese naval and coast guard vessels have become an increasingly common presence around Taiwan. They force the island's navy and coast guard to dedicate significant manpower to shadowing operations, sometimes on a one-to-one or even two-to-one basis. Defense analysts say unmanned vessels offer a cheaper way to maintain continuous maritime awareness over long periods.

Long-endurance unmanned surface vessels could help ease pressure on Taiwan's front-line forces as China expands its "gray zone" operations, said Su Tzu-yun, director of the Division of Defense Strategy and Resources at Taiwan's Institute for National Defense and Security Research.

Gray zone is a term for nonviolent operations that nonetheless wear down a foe's security forces.

"Taiwan's domestic industry has already established a mature production chain for unmanned vessels. What it currently lacks is satellite communication capability, which presents an opportunity for collaboration with U.S. companies to strengthen that aspect," Su told Focus.

Beyond maritime drones

Taiwan is also expanding development of unmanned systems on land. In early June, the National Chung-Shan Institute of Science and Technology unveiled three unmanned ground vehicles, commonly known as "robot dogs." They are based on platforms supplied by Ghost Robotics, a major U.S. military supplier of four-legged robots, and adapted for reconnaissance, surveillance and target identification missions, Reuters reported.

The vehicles could eventually be deployed to offshore islands to reduce troop requirements while improving around-the-clock monitoring. The military has identified an operational need for the systems even though it has placed no formal procurement order yet, according to Jen Kuo-kuang, deputy director of the institute's missile and rocket system research division.

"In fact, the marines believe that on beaches and the coastline, including for the coast guard in Nansha and Dongsha for patrols and inspection, there is a pressing need," he said, referring to the Spratly and Pratas islands in the South China Sea.

Taiwan still has significant room to expand the use of unmanned ground systems, Su said. Given the island's defense-oriented military strategy and favorable geography, he said, deploying such platforms effectively could reduce the exposure of personnel to battlefield risks while strengthening defensive operations.