Chinese research ships are sailing close to or directly above key undersea communications cables around Taiwan as part of an expanding “gray zone“ campaign that is changing the maritime and information environment around the island.
According to a Sky News investigation conducted in conjunction with the Center for Strategic and International Studies (CSIS) and published on Saturday, Beijing is mapping the seabed, monitoring the routes of undersea cables and building up capabilities that could be used in a potential conflict, while also seeking to keep its actions below the threshold of open war.
The report identifies the activity as a new dimension in Beijing’s pressure strategy. While previous “gray zone“ While tactics have focused on air incursions around Taiwan, coast guard patrols and diplomatic pressure, the investigation says the actions are increasingly targeting the information and underwater infrastructure on which Taiwan's economy and the island's ties with its international partners depend.
The investigation tracked several Chinese research vessels operating around Taiwan over the summer and found that they repeatedly passed over key undersea cable routes.
According to the authors, this represents a new stage in Beijing's efforts to shape the future battlefield around Taiwan, encompassing air, land, sea and space, as well as cyberspace and the information environment.
The undersea cable network, made up of isolated fiber optic lines on the ocean floor, carries the majority of the world's internet traffic. Taiwan's connection to the rest of the world depends on a relatively small number of such cables, which Sky News says makes them strategically vulnerable infrastructure.
In 2025, a Chinese national, a ship captain, was sentenced to three years in prison for damaging an undersea cable connecting the main island of Taiwan to the Penghu archipelago — a case that highlighted the vulnerability of this infrastructure. China, for its part, rejects allegations that its vessels are deliberately targeting undersea communications cables.
Taiwan's Ministry of National Defense also reports a trend of increasing activity by the Chinese navy and coast guard during military exercises.
In July, Taipei tracked more than 110 Chinese warships and coast guard vessels operating along the First Island Chain from Taiwan to Borneo, Reuters reported.
Analysts say the combination of unmanned systems, expanded Chinese coast guard operations and a constant naval presence is increasing pressure on Taiwan. Some describe the increasing naval activity as a gradually tightening "noose" around the island.