The cables that carry Taiwan’s internet traffic run along the seafloor, mostly invisible, largely undefended, and increasingly targeted. Since 2023, a sustained pattern of sabotage — carried out by Chinese-linked vessels operating under flags of convenience and falsified identities — has emerged as one of Beijing’s sharpest tools of gray-zone pressure. The plausible deniability is deliberate. So is the damage.
A Documented Pattern, Not a Coincidence
In early 2023, Chinese-registered vessels severed two undersea cables linking Taiwan’s Matsu Islands to the main island, cutting internet access for roughly 13,000 residents for nearly two months. It was framed as an accident. The pattern since has made that framing implausible.
Taiwan’s ruling Democratic Progressive Party has pointed to Chinese vessels disrupting cable operations on 27 separate occasions since 2018. Between January and February 2025 alone, Taiwan experienced four incidents of submarine cable disruptions — three domestic and one international.
The vessels involved share a profile: Chinese-crewed ships registered under third-party flags — Tanzania, Togo, Mongolia, Cameroon — with histories of identity manipulation, AIS spoofing, and obscured ownership chains.
The January 2025 incident involving the Xingshun 39 is illustrative. The vessel used at least two different names, two different flags, and six different Maritime Mobile Service Identities (MMSIs) over a six-month period — an intentional ruse to evade maritime tracking authorities. Taiwan’s deputy digital minister assessed the cable-cutting as likely deliberate, noting that to conclude otherwise, one would need to believe the crew accidentally dropped anchor on the cable, then accidentally engaged the engine with the anchor still down — an implausible sequence.
Weeks later, the Hongtai 58 — a Togolese-flagged vessel with a Chinese crew — severed a cable connecting Taiwan and the Penghu Islands, with its voyage history revealing ties to Chinese interests, frequent name and flag changes, and deliberate ownership concealment. A Taiwanese court subsequently sentenced the vessel’s Chinese captain to three years in prison, finding him guilty of intentionally damaging the cable.
Beijing’s Legal Shield: Civil-Exploitation Lawfare
Beijing’s denials operate on a foundation of international maritime law. Under the United Nations Convention on the Law of the Sea (UNCLOS), primary jurisdiction over a vessel rests with the country of registration — the flag state — which limits other states’ enforcement authority beyond their territorial waters. By routing operations through shadow vessels registered in third countries, China insulates its involvement from direct legal exposure.
The result is a structural gap: Taiwan can identify a vessel, document its behavior, intercept its crew, and still lack the jurisdictional authority to pursue accountability against the actual sponsoring state. Beijing cloaks its sponsorship behind this principle of exclusive flag state jurisdiction — a tactic analysts have termed civil-exploitation lawfare.
China, for its part, characterizes each incident as a routine maritime accident. Its Taiwan Affairs Office has described damage to undersea cables as a “common maritime occurrence” that happens more than 100 times per year globally. The claim is technically accurate about the broader category. Applied to this specific pattern — targeting Taiwanese cables, repeatedly, using vessels with falsified identities, operated by Chinese nationals — it does not hold.
The Hardware Is Now Explicit
China has gone further than deniable gray-zone operations. In early 2025, it publicly revealed a deep-sea cable-cutting device developed by the China Ship Scientific Research Centre — a compact, electric tool capable of severing armored cables at depths of up to 4,000 meters, which is roughly twice the maximum operational depth of most existing subsea communications infrastructure.
The device uses a diamond-edged grinding wheel spinning at 1,600 revolutions per minute, encased in titanium alloy to withstand extreme pressure, and is designed for deployment on submersible vehicles including the crewed Fendouzhe and the uncrewed Haidou series.
This marked the first time any country had officially disclosed the existence of such a capability — and it is explicitly capable of targeting the armored cables that carry more than 95 percent of global intercontinental data traffic.
The strategic logic was noted directly by CSIS analysts: while China continued to claim that any cuts to Taiwan’s cables were accidental, the unveiling of a ship purpose-built for cable cutting made clear that Beijing regards deliberate sabotage of undersea infrastructure as a legitimate coercive tool. Bonnie Glaser of the German Marshall Fund put it plainly: “Beijing insists it isn’t responsible for cutting undersea cables. So why did it just unveil a powerful deep-sea cable cutter?”
Beyond Taiwan: A Global Signature
The same operational signature has appeared in European waters. In November 2024, the Chinese bulk carrier Yi Peng 3 was implicated in the severing of two cables in the Baltic Sea — one linking Germany and Finland, another connecting Sweden and Lithuania — within 24 hours. Joint investigations by Danish, German, and Swedish maritime authorities found physical evidence consistent with deliberate tampering.
In December 2024, the undersea power cable between Finland and Estonia was severed, with suspicion falling on a vessel from Russia’s shadow fleet — itself a parallel architecture of deniable maritime sabotage.
The two shadow fleets — Russian and Chinese — operate via similar mechanisms: beneficial ownership concealment, flag-of-convenience registration, AIS manipulation, and anchor-dragging as a low-signature cutting method. Whether these operations reflect coordinated strategy or parallel adaptation to the same strategic logic, the effect is convergent pressure on the undersea infrastructure of democratic states.
What Severing a Cable Actually Means
Undersea cables carry over 99 percent of intercontinental internet traffic, transmitting terabits of data per second — orders of magnitude beyond what satellite systems can handle. Financial institutions transact an estimated $22 trillion per workday through these cable systems. Disruptions propagate immediately into banking, emergency communications, command-and-control networks, and the basic digital operations of government.
The Matsu Islands precedent is the operational preview. Thirteen thousand residents lost internet access for six weeks. Scale that to Taiwan’s main island — or to the broader Pacific cable network linking Taiwan, the Philippines, Japan, and the United States — and the stakes are not theoretical. Taiwan, the Philippines, and the United States are jointly connected through cable systems including FASTER, E2A, ORCA, the Trans-Pacific Express, and the Pacific Light Cable Network — all of which route through or near contested waters.
Multiple simultaneous cuts in a conflict scenario would overwhelm repair capacity. Security analysts have noted that a handful of simultaneous cable severances in an active conflict zone would strain the global fleet of cable repair ships and could leave regions offline for weeks or months.
Taiwan’s Response
Taiwan has begun treating cable protection as a defense priority rather than a regulatory afterthought. In 2023, the National Communications Commission amended the Telecommunications Management Act to increase penalties for damaging communications infrastructure. In 2024, the Ministry of Digital Affairs designated ten domestic submarine cables, including the Taiwan-Matsu cable, as critical infrastructure subject to heightened government oversight.
In March 2025, Taiwan’s Defense Minister announced active coordination between the Navy and Coast Guard to improve cable monitoring and interdiction capabilities.
The gaps remain significant. Taiwan lacks domestic cable repair vessels, has limited capacity to intercept suspicious ships before they reach international waters, and faces the same jurisdictional constraints that prevent boarding and search of vessels flagged to third states. Taiwan’s deputy digital minister has warned that once a suspect vessel is sailing back to China, enforcement options effectively disappear.
The Strategic Calculation
Cable sabotage fits precisely into Beijing’s gray-zone playbook: high leverage, low attribution, sustained pressure below the threshold of armed conflict. Taiwan’s coast guard has also intercepted Chinese research vessels allegedly gathering seabed data that could be used to locate cables with precision — suggesting that the current sabotage operations are accompanied by intelligence preparation for more systematic disruption.
The pattern — escalating frequency, escalating technical capability, global replication — does not suggest opportunism. It suggests a deliberate campaign to degrade Taiwan’s communications resilience before and during any future confrontation, to test international response mechanisms, and to establish operational precedent under the cover of maritime accident law.
The next severed cable will not be an accident. It has not been for some time.