CNN and environmental news outlet Mongabay tracked eight Chinese research vessels that have undertaken deep-sea mining exploratory missions over the past five years:
During that period, the ships spent only around 6% of their total open water time in areas reserved for exploration by Chinese companies, according to an analysis of data from MarineTraffic, a ship tracking and maritime intelligence provider, and the platform Deep Sea Mining Watch.
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Some have also shown behaviors suggesting attempts to avoid detection, including hundreds of instances of “going dark” by disabling the mandatory Automatic Identification System (AIS), a vessel’s self-reporting system that broadcasts its identity and position.
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Experts say Chinese research vessels may very well be prospecting for minerals beyond their assigned exploration zones: In December 2025 and January 2026, the Shi Yan 6, or “Experiment 6,” appeared to operate within India and Germany’s exploration area in the Indian Ocean; in November, the Chinese vessel Shen Hai Yi Hao, or “Deep Sea No. 1,” appeared to operate within South Korea’s exploration area, also in the Indian Ocean. Throughout 2024, it repeatedly seemed to be operating in other nations’ contracted areas too, including those of Poland, France and Russia.
The South Korean, Polish and French licensees told CNN and Mongabay that China had alerted them in advance to the visits and that research in such areas is permissible under UNCLOS. Germany said it was unaware of the Shi Yan 6’s visit and India and Russia declined to comment.
Experts say the pattern of Chinese activity could reflect a broader strategy to lead in deep-sea mining once commercial extraction begins.
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One of the eight vessels tracked by CNN, the Hai Yang Di Zhi Liu Hao, or “Marine Geology No. 6,” traveled towards a Chinese license area in the Northwest Pacific Ocean in September 2025, but instead appeared to survey an area just outside of it.
On its return, in October, it transited through the Northern Mariana Islands, a US commonwealth that serves as a vital military hub, before loitering up and down its exclusive economic zone (EEZ) and that of Guam, a US territory.
“That’s on the route that US submarines might transit from Guam to places west,” explained Tom Shugart, a former US Navy submarine warfare officer and maritime expert focusing on the Indo-Pacific. Asked about its choice of path, Shugart said it’s “certainly possible” that the Chinese vessel could be leaving behind sensors at 4,600 meters (15,000 feet) below to record a submarine’s unique sound signature.
A month later, in November, the Hai Yang Di Zhi Liu Hao took a week-long journey through Micronesia, an island nation that includes the state of Yap, where the US Air Force is investing $400 million to extend the island’s international airport runway to support American military operations. Guam and Micronesia are considered part of the “Second Island Chain,” a US line of defense against potential Chinese military aggression and a component of US Indo-Pacific strategy under Trump.
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In May 2024, shortly before its visit to a Chinese ISA area, the Xiang Yang Hong 06 (Facing the Red Sun 6), scanned the seabed just west of Guam, a 210-square-mile island in the Pacific Ocean and home to Andersen Air Force Base — a key deployment base for US Air Force bombers and home port to US nuclear attack submarines that could be vital in any defense of Taiwan.
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Taiwan’s Ocean Affairs Council Minister said in January that 41 Chinese research vessels had been detected by the Taiwanese coast guard in waters around Taiwan over the past three years. “They have trampled on our waters, and likely know the ins and outs of waters surrounding us,” Kuan Bi-ling said.
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For example, in November 2023, the Xiang Yang Hong 03 (Facing the Red Sun 03) spent 48 hours doing survey work over a known trans-Pacific cable, covering around 400 square nautical miles — an area smaller than other surveys the vessel conducted, possibly indicating a more targeted investigation to pinpoint objects of interest.
The vessel “made a fairly direct line straight to one particular part of the ocean,” where undersea cables had been laid three years prior, said Mark Douglas, a Starboard analyst. It then continued to do what appeared to be “a very focused little bit of survey work over the course of a couple of days over (the) top of the cable,” before it left the area. Douglas called the vessel’s movements “a smoking gun,” that points to likely dual-use operations.
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In August 2024, the deep sea vessel Ke Xue (Science) transited Alaska’s Aleutian Islands — within the US EEZ — three times before returning to Qingdao, a strategic naval port and the headquarters of the Chinese navy’s North Sea Fleet.
The Xiang Yang Hong 01 made a similar journey. Shortly after operating in its deep sea mining license areas in the Northwest Pacific, the vessel entered the Bering Sea in August 2024 and operated for several days inside Russia’s EEZ, a move described by Ryan D. Martinson of the US Naval War College’s China Maritime Studies Institute as “very rare, maybe unprecedented.” During this visit, the Xiang Yang Hong 01 gained access to Avacha Bay, a key hub for Russia’s Pacific Fleet and submarine forces.
Then, in August 2025, five Chinese research and icebreaking vessels — including the deep sea vessel Tan Suo San Hao (Exploration No. 3) — drew significant attention from the US Coast Guard, after two vessels from the fleet entered the American Extended Continental Shelf (ECS) in Arctic waters west of Alaska.


