When a Taiwanese telecoms company detected that an international undersea cable was damaged earlier this month, it worked to divert internet traffic from the broken line to keep customers on the island connected.
But the company, Chunghwa Telecom, also went to Taiwan’s Coast Guard to report the incident – and a “suspicious vessel” observed on the same route as the affected cable, according to a statement from the company, a major local internet provider.
Taiwan Coast Guard officials in the days since have said they suspect that the Shunxin39 – a Chinese-linked cargo vessel – could have cut the cable, in an incident that has spotlighted the island’s growing concerns about vulnerabilities that could be exploited by Beijing.
Taiwan officials have not cited direct evidence that the ship damaged the cable, and the Taiwan Coast Guard said in a statement Monday that it could not determine the vessel’s intentions. It called for South Korea, the ship’s destination, to help with further investigation.
But the situation has raised concerns among Taiwanese authorities of potential “gray zone operations,” or acts that fall below the threshold of war – in particular those that could hamper the island’s internet and communications with the outside world.
Those concerns come as Taiwan has faced increasing intimidation from Beijing, which claims the self-ruled democracy as its own territory and has vowed to take control of it, by force if necessary.
They also follow a string of incidents in recent years of damage to undersea infrastructure worldwide, including communications cables. Two high-profile incidents in the Baltic Sea involved Chinese ships and remain under investigation.
Taiwan’s Coast Guard said in a statement Monday that the ship suspected of damaging the cable off its northeastern coast last Friday was a Cameroon- and Tanzania-flagged vessel, crewed by seven Chinese nationals.
Such an act could be part of Beijing-backed efforts to use “ships with flags of convenience to cut Taiwan’s international communication as a form of preparation for future blockade and quarantine,” according to the official.
Beijing’s Taiwan Affairs Office said on Wednesday that submarine cable damage is a “common maritime incident,” and balked at Taipei’s “conjecturing” and “deliberate framing of gray zone threats.”
Chinese national Guo Wenjie, director of the company operating the vessel, denied in a statement to news agency Reuters on Wednesday that the ship was responsible for the damage.
A new ‘gray zone’ tactic?
In 2023, Taiwanese authorities blamed two Chinese ships for damaging two submarine internet cables linked to Taiwan’s outlying island of Matsu in incidents days apart causing an internet blackout, but stopped short of saying they were deliberate acts.
Su Tzu-yun, a military expert at Taiwan’s Institute for National Defense and Security Research, said more evidence is needed to say whether the latest incident was intentional.
But he said Taiwan needs to bolster maritime surveillance and defense of submarine cables.
“Once submarine cables are sabotaged, Taiwan’s connectivity to the international community will be severed; we can then only rely on bandwidth provided by satellites, which would then affect our digital economy, international trade and banking,” he said, calling such potential sabotage a form of “psychological warfare.”
Other observers have suggested the recent incident could be part of a trial of such tactics.
“While it doesn’t look to me like part of an effort to seriously impede Taiwan’s connectivity with the world … it could be consistent with either a campaign to apply low-level harassment, or as a test run for something that could be done at a larger scale at a later date in conjunction with other coercive operations,” said Tom Shugart, a retired US Navy captain and adjunct senior fellow at the Center for a New American Security think tank in Washington.
Taiwan has seen a surge of Chinese military activities in the Taiwan Strait and the Western Pacific in recent months, in line with a ramping up of intimidation over the past few years. Chinese naval and coast guard vessels have plied regional waters, and there has been an increase in Chinese aircraft operating around the island.
But Taiwan officials and defense experts have increasingly focused on the potential for Beijing to use gray zone tactics and non-military actors like China Coast Guard and various police and maritime safety agencies – as well as a so-called maritime militia of civilian ships – to quarantine the island or play a role in a blockade if it wanted to move to take control.
In a first-of-its kind “tabletop” exercise simulating military escalations by China late last month, multiple government agencies were tasked with responding to a broader base of threats than an armed invasion, including information warfare.
One official highlighted then how government agencies struggled to clarify falsehoods during electricity or internet outages, highlighting the need for Taiwan to have a backup mechanism to ensure the flow of information.
Taiwan’s Ministry of Digital Affairs earlier this week said it has been working on initiatives aimed at strengthening Taiwan’s communications by exploring alternative internet options including low-Earth-orbit satellites and adding new submarine cable stations.
Last month, Taiwan’s tech tzar Wu Cheng-wen told reporters in a briefing that in addition to working with LEO satellite company OneWeb, the island is also in talks with Amazon’s Project Kuiper for satellite collaborations.
A spate of sabotage?
Those efforts may only appear more urgent to observers amid a spate of incidents where Chinese and Russian vessels have come under scrutiny.
Swedish police have sought to investigate the Chinese bulk carrier Yi Peng 3 in relation to its possible role in the breach of two undersea fiber-optic cables in the Baltic Sea in November. The incident had echoes of a 2023 case in which Chinese ship NewNew Polar Bear was suspected of damaging undersea cables as well as a gas pipeline in the Baltic.
Finnish investigators late last month seized a tanker carrying Russian oil and said they suspected the vessel had damaged the Finnish-Estonian Estlink 2 power line and several internet cables by dragging its anchor across the seabed.
Damage to submarine cables in the Red Sea last March disrupted telecoms networks in the region weeks after the official Yemeni government warned of the possibility that Houthi rebels would target the cables, though the group denied involvement.
While damage to cables is not rare and is often seen as accidental, analysts warn that the recent cases also underscore vulnerabilities.
Shugart of CNAS said that there does seem to be a number of breakages recently that seem to have been deliberate, including those done “by or for Russian or Chinese interests.”
“This is going to be a quite challenging issue to police, as most of these cables run through international waters where traditional international law allows enforcement only in very narrow areas,” he said.
