January 16, 2025
TAIPEI – The recent severing of an undersea cable off Taiwan has underscored how important it is for the island to strengthen its communications resilience, amid concerns that the critical subsea systems connecting it to the rest of the world may become a target of sabotage in a potential conflict.
On Jan 15, Taiwan’s National Security Bureau said that it plans to step up the monitoring of ships flying so-called flags of convenience, referring to vessels that are registered to countries other than their owners’.
If these ships come close to undersea cables and enter within 24 nautical miles of Taiwan’s coast, the coast guard will board them for investigations, the bureau added in its report to lawmakers ahead of ministers taking questions in Parliament on Jan 16.
While such measures will be useful for now, it remains to be seen if they can achieve a strong enough deterrent effect in the longer term, according to Mr Ian Li Huiyuan, a military expert at the S. Rajaratnam School of International Studies.
“Such ships do exist for innocent reasons – for example, it could simply be cheaper to register a ship in a certain country,” he told The Straits Times. “So it may tax Taiwan’s ability to manage the situation if they’re having to monitor all flag-of-convenience vessels.”
The proposal comes after Taipei said that a China-linked cargo vessel, the Shunxing-39, damaged an undersea data cable to the north of the island on Jan 3. The ship sailed under the Cameroon flag and was also registered in Tanzania, but it was owned by a Hong Kong company, according to Taiwanese officials. All seven crew members on board were Chinese nationals, said Taiwan’s coast guard.
The incident caused minimal disruption to the island’s web traffic after Taiwan’s Chunghwa Telecom rerouted data to other cables, and there is no direct evidence that the damage inflicted was deliberate.
However the situation has raised concerns among the Taiwanese authorities of it being a possible act of sabotage.
“It is not possible to confirm the real intention of the vessel. However, we cannot rule out the possibility of a Chinese flag-of-convenience ship engaging in grey-zone harassment,” the Taiwan coast guard said in an earlier statement.
In response, China’s Taiwan Affairs Office said damage to undersea cables is a “common maritime accident” and that Taiwan was making accusations “out of thin air”.
Taipei has, in recent years, complained about Beijing stepping up its grey-zone warfare – the use of irregular tactics to weaken an adversary without resorting to open combat – in its long-term goal to pursue “reunification” with the island, which it claims as its own territory.
For instance, China has sent balloons and drones into Taiwan’s air-defence identification zone, aimed at intimidating the public and undermining the morale of the military.
Taipei’s alarm surrounding the Shunxing-39 came in the wake of a similar case in the Baltic Sea after a Chinese bulk carrier was linked to the severing of two undersea cables in Swedish territorial waters in November 2024.
In February 2023, the 14,000 residents in Taiwan’s outlying Matsu islands were knocked offline for several weeks, when the only two submarine cables connecting them to the main island were severed by passing ships flying Chinese flags.
The fact that the double damage was done in quick succession, with the second cable being severed within days of the other, startled officials.
In the case of the Shunxing-39, marine data tracking services showed that the vessel had sailed short laps in the waters near northern Taiwan since December 2024, which experts say is unusual.
“The ship made multiple ‘figure eights’ in the water, which could be an indication that it was dragging its anchor across the seabed to cut the cable,” said Dr Su Tzu-yun, a military strategy expert from the Institute for National Defence and Security Research, a Taiwanese think-tank.
If the act was indeed intentional, Dr Su said he believed it was designed to create unease among the Taiwanese public.
“If Taiwan’s undersea cables are completely cut off, its connections to the world are cut off,” he added.
International internet traffic is mostly carried through fibre-optic cables on the ocean floor, with Taiwan connected to the world through 14 such cables.
The cable that was most recently damaged is part of the Trans-Pacific Express Cable System, a nearly 18,000km-long system that connects Taiwan to the US, among other countries.
Damage to undersea communications infrastructure is not rare. According to the UK-headquartered International Cable Protection Committee, there are 150 to 200 cable faults globally every year, mostly caused by fishing and trawling, as well as natural hazards.
However experts are increasingly worried that the vulnerability of these critical systems – which could take weeks to repair if damaged and is a costly affair – could be taken advantage of amid heightened geopolitical tensions.
That is not a new idea. During World War I, the British cut German submarine telegraph cables to force the Germans to communicate on radio where it could be intercepted more easily.
Professor Geoffrey Till, an emeritus professor of maritime studies at King’s College London, said that the latest cable-cutting incident near Taiwan could be part of Beijing’s preparations for war.
“By cutting the cables, China can potentially test the vulnerabilities in Taiwan’s undersea cables, see the extent of network disruption and how long it takes for Taiwan to remedy the damage,” he told The Straits Times.
“As with all grey-zone tactics, it is not immediately clear that the state had instructed the commercial ship owner to cut the cables,” he added, which makes it difficult for affected parties to seek recourse.
Besides its plans to step up surveillance of passing ships, Taiwan has taken a leaf out of Ukraine’s handbook by setting up a backup satellite internet network for emergencies, which has proved to be crucial in keeping locals online amid Russia’s invasion.
So far, Taipei has placed 700 satellite receivers across the island, some of which have already proved useful after a 7.4-magnitude earthquake damaged telecommunications base stations in April 2024.
At the same time, Taiwan has embarked on an ambitious NT$4 billion (S$165 million) project to develop its own satellites to ensure backup connectivity during emergencies, with the first of two indigenous satellites to be launched into space in 2026.
But such satellite networks will not replace subsea cables anytime soon, given that the fibre-optic cables deliver much faster internet speeds, can carry higher traffic loads and are more cost-effective.
“If submarine cables are sabotaged, Taiwan would only be able to rely on bandwidth provided by satellites, which would affect our digital economy, international trade and banking,” said Dr Su, the defence expert.
“Taiwan needs to invest more resources in protecting the undersea cables.”
- Yip Wai Yee is The Straits Times’ Taiwan correspondent, covering political, socio-cultural and economic issues from Taipei.
- Additional reporting by Yew Lun Tian.