On 11 April 2025, Taiwanese prosecutors filed charges against a Chinese ship captain, accusing him of deliberately damaging undersea cables off the coast of Taiwan in February 2025. The Chinese-crewed ship Hong Tai 58, registered in Togo, was seized after it was suspected of having damaged an undersea cable off southwestern Taiwan. The Tainan District Prosecutors’ Office said that the captain was charged with violating the Telecommunications Management Act. This marked the first time when Taiwan prosecuted anyone for such an offence. The unprecedented legal action follows a surge in cable malfunctions that has raised concerns among Taiwanese officials amidst heightened tensions with China.
As per the news, on 25 February 2025, authorities boarded the Hong Tai and detained its seven Chinese crew after Chunghwa Telecom Co. reported to the Coast Guard Administration (CGA), that its Taiwan-Penghu No. 3 submarine fiber optic cable had been severed. The CGA also said that it had spotted Hong Tai in the area since 22 February 2025.
The prosecutors explained that it was during this time, the ship dropped its anchor 5 nautical miles (9.26km) west of Tainan’s Beimen District and sailed in a sabotaging zigzag pattern around the No. 3 cable. Investigators found that the ship’s electronic navigational chart showed the locations of various undersea cables around Taiwanese waters, including the No. 3 cable.
Reportedly, the crew was not charged due to a lack of evidence and awaits deportation, while the captain has since been held separately. They added that ‘the captain continued to deny any wrongdoing and refused to reveal the identity of the shipowner who likely instructed him to carry out the act’.
These damaging actions closely follow China’s launch of a compact, deep-sea, cable-cutting device, capable of cutting lines at depths of up to 4,000 metres (13,123 feet) in February 2025. The tool, first announced in the Chinese-language journal Mechanical Engineer, has a titanium alloy covering and specialised seals that can withstand the intense pressures of 4000 metres depth for long periods. It also features a ‘grinding wheel covered in diamond edges, spinning at a rapid 1,600 revolutions per minute’, which gives the device the ability to cut through the protective steel layer encasing a cable, designed to target armored cables. It, reportedly, has twice the maximum operational range of the existing subsea communication infrastructure. The device is developed by the China Ship Scientific Research Centre (CSSRC) and its affiliated State Key Laboratory of Deep-sea Manned Vehicles. The device has been designed to ‘integrate with China’s advanced submersibles, both crewed and un-crewed, such as the Fendouzhe (Striver) and the Haidou series’.
In the last decade, China has attained considerable undersea capabilities that are concerning for neighboring countries. But this disclosure marked the first time a nation has publicly acknowledged possessing such a disruptive asset, capable of compromising vital digital infrastructure, despite its official purpose of enabling seabed civilian salvage and mining operations.
China has been accused of sabotaging international telecommunications cables earlier as well. These grey-zone operations are a threat to international communication and the financial systems, and damaging undersea cables is seen as an international crime. The prosecution of the captain can snowball into an international action against China, especially considering the Trans-Pacific Express cable, worth USD 500 million, has linked countries in East Asia with the US’ West Coast since 2008. Taiwan has sought help from its European partners to avoid any future communication blackouts. These actions could also strengthen support for Taiwan against Chinese actions that undermine global connectivity and stability.
It is important to understand the larger impact of prosecuting the captain and the gravity of this incident. Enforcing its law on a Chinese national, Taiwan is asserting Taiwanese legal and political sovereignty. The undersea cables fall into critical infrastructure, a national security concern; therefore, by doing this, Taiwan is declaring to China that it will protect its critical infrastructure against threats as a fundamental duty of any independent nation. This action is also setting a legal precedent. China uses the grey-zone operations to test boundaries, and such actions often go unpunished, for lack of domestic legislation or evidence. Taiwan turning the grey-zone action into a criminal offence will also provide a basis for using domestic laws against future grey-zone warfare tactics by China, which could deter frequent attempts at damaging cables.
For Taiwan, this is also a simple but critical matter of survival. China poses an existential threat to Taiwan’s sovereignty. Denouncing the Taiwanese government as “separatists” and vowing to thwart all actions seeking Taiwanese independence, China has escalated military exercises around Taiwan since 2022. A communication blackout is key to China’s strategy of blockade. Therefore, frequent damage to expensive international undersea cables poses a serious challenge to the security of Taiwan.
Taiwan’s decision to prosecute a Chinese ship captain for deliberately damaging undersea communication infrastructure is more than a legal action; it is a strategic assertion of sovereignty in the face of escalating grey-zone pressures. By turning a covert sabotage act into a criminal offence, Taiwan is drawing a clear legal and political line, signaling its intent to defend its critical infrastructure with rule-of-law instruments.
This case also sets a vital precedent. The undersea cables are the unseen blood veins of the global internet and financial systems, and due to these frequent actions of sabotage, they are emerging as a frontline in modern geopolitical conflict. As China develops increasingly sophisticated tools to operate in this domain, including publicly acknowledged cable-cutting devices, the stakes for regional security and global connectivity rise sharply. Taiwan’s assertiveness, if supported by international legal, technical, and diplomatic frameworks, could become a model for other nations seeking to deter grey-zone coercion. Ultimately, for Taiwan, safeguarding its cables is not just about preserving communication; it’s about preserving sovereignty and securing survival in an increasingly contested strategic environment.