Taiwan heavily relies on undersea cables to ensure digital connectivity. Indeed, 90% of its internet connectivity depends on such cables.
This reliance is not unique — undersea cables carry roughly 99% of global communications — but for Taiwan, the stakes are higher than for most. Sabotage, natural hazards, and cyberattacks leave Taiwan’s undersea cables highly vulnerable.
A disruption could cut businesses off from international partners, paralyze the financial sector, hinder government operations, and obstruct military command and control. In short, undersea cables are one of Taiwan Achilles’ heels.
The incident that occurred on Feb. 2, 2023, when two undersea cables linking Taiwan to its Matsu Islands were severed, cutting off normal communication for nearly two months, illustrated how easily Taiwan’s communication system can be destabilized, whether by accident or design. It also revealed how much Taiwan’s defense readiness, economy, and society hinge on the protection and maintenance of undersea cables.
Taiwan must therefore take decisive measures to safeguard access to its submarine cables, which are central to its security and future resilience.
Resilience matters
Connectivity underpins critical infrastructures, military operations, government continuity, and social engagement. Without it, emergency coordination breaks down, supply chains collapse, and social trust erodes.
For Taiwan, the stakes are amplified by its geopolitical situation. Disruptions of cables provides fertile ground for Chinese hybrid warfare tactics.
By creating uncertainty about government competence and disseminating fear of isolation, Beijing can easily destabilize Taiwan. A fragmented population, burdened by distrust and anxiety, would weaken national resolve and resilience.
Moreover, while military capabilities often dominate discussions of Taiwan’s security, digital resilience plays an equally important role. The Ukrainian conflict perfectly exemplifies how important, and vulnerable, connectivity is to sustaining war efforts.
In this regard, the fact that nine of the 15 undersea cables connected to Taiwan are in part owned by Chinese enterprises reflects the critical gap in Taipei’s security framework, even if it does not directly translate into outright dominance.
This makes submarine cables both indispensable and dangerously exploitable –– a reality already identified by Beijing.
Hybrid threats
Sabotage of undersea infrastructure is a low-cost, high-impact tactic. Cutting a cable can take minutes, while repairs can take weeks. Suspected Chinese fishing and survey vessels operating in contested waters already raise concerns about gray zone tactics aimed at probing or threatening these networks.
Cyber intrusions into cable landing stations add another layer of risk, enabling espionage or disruption at critical nodes. By gaining control of these stations, Beijing could have the freedom to manipulate or block the optic signals, consequently dominating the digital environment of the island.
As highlighted by the Global Taiwan Institute, Chinese sabotage of submarine cables can serve various objectives. It allows Beijing to observe how Taipei responds to hybrid threats and to expose the nation’s weaknesses. It also contributes to spreading instability and uncertainty among Taiwanese.
Collecting real-time data also raises the People’s Liberation Army's readiness and strategic knowledge necessary to execute a Taiwan contingency, for which cutting off lines of communication will certainly be one of the first and most important goals. This is especially true for the offshore islands, whose communication would be severely disrupted if undersea cables were severed.
These threats make Taiwan’s undersea cables one of its most acute vulnerabilities. They are strategic chokepoints in both war and peace, fragile by design and difficult to defend.
Paths to mitigation
Therefore, Taiwan cannot fully secure its cables alone. Given the vital importance of undersea cables for the international community, safeguarding them requires international cooperation.
The current legal protections are insufficient. The UN Convention on the Law of the Sea provides only vague safeguards and lacks mechanisms to hold saboteurs accountable. Strengthening international legal frameworks would help raise the costs of interference and clarify responsibilities.
Equally important, like-minded countries must recognize that any disruption to Taiwan’s undersea cables will have a profound impact on the global economy and that they must therefore strengthen Taipei’s maritime defenses and capabilities. A peaceful and secure Taiwan Strait is essential to reducing China’s shadow fleet effectiveness.
However, this does not prevent Taipei from taking decisive measures to protect its economic and security stakes. Domestically, Taipei has taken steps. The Ministry of Digital Affairs, with the Telecom Technology Center, has deployed Middle Orbit Satellite Signal for Taiping Island, boosting communications by approximately 3.9 times.
The digital ministry has also launched emergency roaming systems, introduced non-geostationary satellites for crisis response, and diversified cable routes. The Taiwan–Philippines–United States line, expected in 2026, will likely reduce exposure to sabotage and tighten links with Washington.
Still, more is needed. Criminalizing cable damage could enhance deterrence, though it risks escalation with Beijing. Taiwan must also reduce reliance on foreign repair crews by building its own repair capacity.
Cooperation with Japan and the United States — both leaders in this field — remains essential. The EA2 Cable Project is one example of how trilateral initiatives can reinforce resilience.
Elevating 10 undersea cables to “critical infrastructures” status has been an important milestone, unlocking new resources and embedding cable security within Taiwan’s broader defense strategy. The securitization of its cable landing stations must also be a priority for Taipei as any attack against the nation’s cable landing stations would profoundly disrupt its digital infrastructure.
Taiwan should bolster early warning and monitoring against cable sabotage. A solution could be to rely on Distributed Acoustic Sensing, which turns fiber into a real-time sensor, detecting and tracking activity along the cable. This data can in turn be used to take informed actions to impending sabotage.
Shifting regional landscape
There are multiple solutions, but safeguarding cables and strengthening Taiwan’s digital resilience require a comprehensive and cooperative strategy that addresses vulnerabilities and reduces the effectiveness of China’s gray zone tactics.
Implementing this strategy starts with recognizing the current opportunities –– geopolitics is reshaping Asia’s cable networks.
Since 2019, US restrictions on Hong Kong and China’s growing control over undersea projects have forced trans-Pacific cables to bypass traditional routes, redirecting traffic through Guam and the Philippines.
For Taiwan, the reshaping of regional connectivity can be turned into an advantage. By partnering more closely with Japan and the Philippines, Taipei can transform itself from a dependent node into a regional internet hub.
Such a role would carry multiple benefits. First, it would provide redundancy for Taiwan’s own communications, reducing exposure to sabotage or natural disasters. Second, it would embed Taiwan more deeply into regional and global digital supply chains, further reinforcing the fact that its stability represents a shared interest for partners and allies.
Taiwan cannot turn cables into a strength, but it can make them harder to exploit and less likely to be destabilized –– and this is essential for Taiwan’s future.
