As the world becomes increasingly digitized, efficient and reliable global connectivity has become essential. However, despite the rising virtualization, it is essential to keep its physical backbone in mind. At the heart of this global connectivity lies a vast network of real physical undersea cables. These cables carry over 95 percent of international data, supporting high-bandwidth connections critical for a wide range of functions. Ranging from global communication, financial transactions, scientific research, to security matters. Given their strategic importance, damage to undersea cables can have far-reaching consequences.
Taiwan´s Streets Pixabay by Tigao
In recent years, undersea cable disruptions have become a growing global concern, with high-profile incidents such as the 2024 Red Sea Cable Cut and repeated damages at the Baltic Sea. These events are increasingly viewed in connection with state actors, particularly Russia and China. Similar patterns also occur at the Taiwan Strait. Given the Strait’s strategic significance and the persistent threat posed by China’s grey zone activities, undersea cable security in this region warrants closer scrutiny. How will this strategic hub shape global corporation and Taiwan´s role as a centre of a connectivity within?
Taiwan’s Digital Lifelines at Risk
Taiwan is home to one of the most important information hubs and semiconductor manufacturing centres. Beneath the Strait lies around 14 international undersea cables connecting the region to global networks, along with 10 domestic cables serving internal needs. These undersea cables are vital not only to international digital connectivity but also to Taiwan’s national security. Cables that connect Taiwan’s main island to its outlying areas like Matsu Island. Serve as a critical communication link between the core territory and its outer island. Any disruption to these connections can have serious implications for both civilian life and defence communications, especially amid growing threats from China.
Undersea cable disruptions can be caused by both natural factors like wire aging and human activities like civilian fishing. However, there is growing suspicion of intentional sabotage around Taiwan. Since 2023, there has been a noticeable increase in cable disruptions near Taiwan. As of now, Taiwan has already experienced four incidents since the beginning of this year. With two cases strongly suspected to be deliberate.
The first occurred on January 3, involving the Trans-Pacific Express cable system, where the disruption was linked to a suspected Chinese-related vessel, Xingshun 39. The second incident took place on February 25, affecting Taiwan- Matsu Network No. 3, and was tied to a Togo flagged cargo, Hongtai 58, believed to be China-related. In a landmark move, the Chinese ship captain was charged for damaging the cable. Marking the first time Taiwan has issued a formal legal charge in such a case.
These deliberate acts, combined with two additional incidents attributed to natural deterioration, reflect a troubling pattern of continuous undersea cable disruption at the Strait. Raising serious concerns for Taiwan’s security and resilience. While Kenny Huang, Executive Director of the Taiwan Network Information Center (TWNIC), has asserted, given Taiwan’s existing backup system, sole network disruptions are unlikely to significantly impact daily activities. However, the severing of even a single domestic cable increases reliance on the remaining infrastructure. Without accounting for the compounded impact of multiple simultaneous disruptions. If these disruptions persist, they could undermine the stability of essential communication links and increase Taiwan’s overall vulnerability.
| Undersea Cable Disruption 2025 (till May) | Cable | Domestic/ International | Cause | Repair Length |
| Jan 3 2025 | Trans Pacific Express Cable | International | Suspect vessel sabotage Xingshun 39 (Hong Kong Registered) | till Jan 20 2025 |
| Jan 15 2025 | Taiwan- Matsu No. 3 | Domestic | Natural deterioration | till March 2 2025 |
| Jan 22 2025 | Taiwan- Matsu No. 2 | Domestic | Natural deterioration (initial damage) | – |
| Feb 16 2025 | Taiwan- Matsu No. 2 | Domestic | Natural deterioration (total disconnection)) | till March 14 2025 |
| Feb 25 2025 | Taiwan- Penghu No. 3 | Domestic | Suspect vessel sabotage Hongtai 58 | Pending info |
Since most undersea cables are mostly privately owned, like SubCom from the U.S., NEC from Japan and the rapidly emerging Huawei Marine Network from China, poses a special challenge. Consequently, Taiwan without its own emergency repair team needs to rely on external assistance. When disruptions occur, Chunghwa Telecom, Taiwan’s main telecommunications provider, is tasked with contacting international cable maintenance agencies and coordinating with repair vessels to fix the damaged lines. However, repair priority is typically given to international cables over domestic ones. If multiple cables are damaged within the same repair zone, vessels follow a queue based on international scheduling rules. Only when no higher-priority repairs are required can the vessel be dispatched immediately to address Taiwan’s cables.
The repair timeline is further complicated by a range of logistical and regulatory factors, including contractual obligations, fishing seasons, weather conditions, maritime usage permits, and relevant jurisdictional laws. The cable ship must submit a proposed repair plan to the operators, who must approve both the timeline and the costs before the mission proceeds. Hence, Taiwan cannot respond swiftly, especially when the damaged cables are domestic rather than international. This delayed response increases the vulnerability of critical communication links, particularly those connecting the main island to outlying areas like Matsu.
Sabotage or Accident? China’s Grey Zone Tactics at the Taiwan Strait
For Taiwan, the disruption of undersea cables is increasingly viewed as part of China’s ongoing grey zone tactics at the Strait. Aimed at undermining Taiwan’s security and resilience without triggering open conflict. Although China consistently denies involvement and often attributes these incidents to maritime accidents. The frequent presence of Chinese-linked vessels or personnel in such disruption lends credibility to suspicions of intentional sabotage.
Adding to these concerns, in March, China unveiled they have developed a deep-sea cable-cutting device, reportedly capable of severing even the world’s most fortified underwater communication and power lines. While the device was introduced under the banner of civilian applications such as seabed mining and salvage operations. Its dual- use potential cannot be ignored. This technological development is yet another indication of China’s growing capacity to exploit vulnerabilities below the surface as part of broader grey zone operations.
Importantly, the danger is not confined to the Taiwan Strait. China has also been suspected of involvement in similar undersea cable concerns in the Baltic Sea, allegedly in support of Russian interests. This suggests that the security of global undersea cable networks—critical to international communications and economic stability—could increasingly be at risk, extending the relevance of Taiwan’s experience to beyond.
Legal Challenges in Securing Undersea Cable
Despite growing recognition of undersea cables as critical infrastructure. The current international legal regime remains fragmented and limited to prevent and respond to cable damage. The United Nations Convention on the Law of the Sea (UNCLOS) serves as the main legal instrument governing submarine cables. It affirms the freedom to lay and maintain submarine cables in the Exclusive Economic Zone (EEZ) and on the high seas (Articles 58, 79, and 112). It also obliges states to criminalize the intentional or negligent damage of such infrastructure (Articles 113–115). This legal gaps, come along two essential challenges, first of all referring to the enforcement gaps and attribution problem and secondly dealing with the obstacles to identify responsible actors due to the flag of convenience and ownership ambiguity.
- Enforcement Gaps and Attribution Problem
One of the key legal challenges lies in determining whether damage is accidental or deliberate. Human activities such as fishing and anchoring frequently cause unintentional cable breaks, making it difficult to conclusively prove sabotage. This ambiguity is compounded by the lack of robust international mechanisms for investigation and prosecution. When incidents occur in international waters or EEZ. Without clear evidence and cooperative legal frameworks, attributing intent remains challenging, which weakens deterrence and accountability efforts.
- Flag of Convenience and Ownership Ambiguity
These enforcement gaps are further complicated by the widespread use of flags of convenience. Vessels are often registered in jurisdictions with lax oversight, obscuring the true identity and ownership of the ship. For example, in the damaging of the Taiwan- Matsu No. 2, the cargo was registered under a Togolese flag. However, Taiwan’s coast guard suggested that the flag was likely a flag of convenience, as all eight crew members onboard were Chinese nationals. The cargo was also found to be linked to at least three different ship names to the same maritime identification number. These opaque arrangements complicate investigations and raise serious doubts about intent and accountability in undersea cable incidents.
Securing the Unseen: Taiwan’s Response to Rising Undersea Cable Threats
Facing increasing vulnerability and urgency surrounding undersea cable security, Taiwan launched the Regional Response Platform for Submarine Cable Security shortly after two major incidents involving damage to the Taiwan–Matsu cables in early 2025. This platform coordinates responses to cable-related crimes by bringing together the island’s Coast Guard, prosecutors, telecommunications operators, and investigators.
Beyond regulatory coordination, Taiwan has incorporated both technological and legislative measures to strengthen cable security. The Submarine Cable Automatic Warning System (SAWS) automatically issues alerts to nearby vessels, warning them against anchoring in restricted zones. Stricter Port State Control (PSC) inspections have been implemented for foreign vessels registered under flag states with histories of false entry declarations like China, Hong Kong. If such vessels approach Taiwan’s restricted waters near outlying islands close to China, or enter SAWS-designated warning zones. Authorities are empowered under the Coast Guard Act to board the ship and verify its Maritime Mobile Service Identity (MMSI) and Automatic Identification System (AIS) data for potential violations.
However, Taiwan’s efforts continue to face challenges stemming from the ambiguity of the international legal framework governing undersea cables. While initiatives such as QUAD cooperation on cable security mark a step forward in regional collaboration. Taiwan’s exclusion from formal multilateral mechanisms raises questions about how it can independently enhance its resilience. One practical challenge arising from this exclusion is Taiwan’s limited access to shared regional repair resources and coordination frameworks. Potential delays in intelligence sharing and restoring damaged infrastructure.
Given these constraints, Taiwan may need to explore alternative pathways to enhance its resilience. Could deeper cooperation with like-minded partners? The creation of a dedicated rapid-repair capability? Or stronger domestic enforcement offer viable solutions- enabled under UNCLOS Article 113, which obliges states to criminalize the negligent or intentional damaging of undersea cables? Yet such actions—particularly increased enforcement—risk triggering further tensions with an already assertive China, underscoring the strategic complexity of safeguarding critical infrastructure in a contested environment. Concluding, even so the world is becoming more virtual, so the consciousness for its physical backbone has to be increased, as global connectivity depends on a framework for resilient undersea cables and reliable corporations. Could this be a chance for Taiwan to build new forms of networks?
Question for Reflection:
- Can Taiwan frame cooperation on undersea cable security as an initiative to reintegrate into multilateral frameworks from which it is currently excluded?
- What options does Taiwan have to address growing Chinese threats to undersea cable security and the broader risks they pose to its national resilience?
- Is the current international framework truly equipped to address the growing threat of undersea cable sabotage, especially given the challenges of amending or updating international law?
Further Readings……
Freund, A., Feb 2025. How sabotage on undersea cables affects our digital world. DW News.
Goldenziel, J., Feb 2025. Law Can’t Stop Submarine Cable Sabotage. Russia And China Know It. Forbes.
