China Is Practicing How to Sever Taiwan’s Internet

As the United States was watching the skies in the aftermath of the spy balloon incident, China may have been acting at sea. In early February, maritime vessels disabled the two undersea cables connecting Taiwan’s Matsu Islands, a tiny archipelago just 10 nautical miles off China’s coast, to the internet. Now residents of the islands face highly reduced internet connectivity until the cables are repaired. The activity looks like targeted harassment by Beijing—or an exercise in preparation for cutting off the whole of Taiwan.

On Feb. 2, a Chinese fishing vessel sailing close to the Matsu Islands severed one of the two cables, which connect the islands with Taiwan proper. Then, six days later, a Chinese freighter cut the second cable. Speaking shortly after the second cable was cut, Wong Po-tsung, the vice chair of Taiwan’s National Communications Commission, told reporters that there was no indication the incidents were intentional. It’s not uncommon for undersea cables to be damaged—but losing two in a row is either really unfortunate or quite possibly not a coincidence. Either way, Matsu Islands residents are now left with only rudimentary internet access: The islands’ commercial telecommunications provider, Chunghwa Telecom (CHT), has set up free, round-the-clock Wi-Fi in its stores on the islands and launched a backup microwave system for phone calls and state communications.

The Matsu Islands’ 12,700 or so residents will have to live without the cables for many more weeks; a repair vessel will arrive on April 20 at the earliest, and the repairs will require further time. The residents have experience living with damaged undersea cables. CHT reports that the cables were damaged five times in 2021 and four times last year, though nowhere near as badly as this time. During such periods of impaired internet connectivity, “it would take more than 10 minutes to send a text message, and sending a picture would take even longer,” Lii Wen, the Matsu Islands head of the ruling Democratic Progressive Party (DPP), told the Taipei Times, adding that “the booking system in hostels and logistics services cannot function normally either, let alone viewing content and films on social media.”

With both cables down, even moderately slowed-down internet immobilizes daily life. Beijing is watching to see how island residents get on with this impediment to their existence—and to see how they manage to communicate with Taiwan proper. It’s also keeping close military watch of what it considers a renegade region. Taiwan’s offshore islands have always been its Achilles’s heel; in 1958, China shelled the Matsu Islands and the neighboring island of Kinmen. Last summer, the People’s Liberation Army Navy conducted large exercises near the island, purportedly in response to then-U.S. Speaker Nancy Pelosi’s visit to Taiwan, though their large and well-executed nature suggested they had been planned long in advance.

Indeed, it’s striking how often Chinese vessels have damaged the undersea cables connecting islands in recent years. It’s especially striking because it’s no mystery where the world’s 380 undersea cables are located. On the contrary, there are maps detailing their location to ensure that fishing vessels don’t accidentally harm them while dragging their nets. By and large, this works: The International Cable Protection Committee reports that each year there are between 100 and 200 cases of damage to the cables and only 50-100 of those incidents involve fishing vessels; the rest are the result of construction and other activity. The incidents involving damage to the cables connecting the Matsu Islands are, in other words, disproportionately frequent.

What’s more, to date they have primarily involved the Chinese excavators that park themselves off the islands and dig up sand (which I wrote about for Foreign Policy last year). Given that undersea cables have a diameter of 17-21 millimeters (roughly the size of a garden hose), it would require an unbelievable amount of bad luck to accidentally damage them as often as Chinese vessels do—let alone to take out two in a row.

Chinese excavators parking themselves in Taiwanese waters and taking Taiwanese sand are classic gray-zone aggression: It’s not a military attack, but it’s also not nothing. Indeed, every time they appear, Taiwanese coast guard vessels have to travel to the site and instruct the vessels to leave (though they can’t be sure the uninvited visitors will do so in an expeditious manner). Every time, the diggers harm the maritime wildlife and the seabed. And because they often harm the undersea cables in the process, they harm the Matsu Islands’ ability to function and to communicate with Taiwan proper and the wider world.

Given that the undersea cables’ locations are known, this frequent and now jacked-up harm to the Matsu Islands doesn’t look like accidental damage—it looks like harassment of Taiwan. After the most recent incident, the DPP accused China of deliberately damaging the cables given how often they’re broken. The incidents could even be an exercise in preparation for a communications cutoff of Taiwan proper. Fifteen undersea cables connect the main island with global telecommunications.

CHT plans to, at least partly, ensure the Matsu Islands’ connectivity by laying another cable, and this time it will be buried underneath the seabed. The cable will, however, only be in place in 2025. In the meantime, CHT has to pay for the backup internet system, and it’s also waiving island residents’ internet fees. When the repair ship arrives, fixing the two cables will cost CHT between $660,000 and $1.3 million.

Causing such costs is also part of gray-zone aggression. If a company suffers losses as a result of geopolitical aggression, its insurer may not cover it: Russia’s devastating NotPetya cyberattack resulted in massive lawsuits between multinationals and their insurers. While CHT’s conversations with its underwriter are naturally confidential, the two will have to agree on whether the severing of the cables was accidental damage or an act of harm initiated by another government to weaken Taiwan. Either way, CHT or its insurer has to pay for repeated damage that goes far beyond what’s typical for undersea cables. What happens if CHT backs out of providing connectivity to the Matsu Islands on the grounds that constant cable repairs are making it too difficult and expensive? As I’ve outlined in other pieces and this report, geopolitical confrontation risks making parts of global business uninsurable.

And there’s another problem facing CHT, Taiwan, and indeed every country: the shortage of cable ships. The reason CHT has to wait until the end of April, or later, for repairs to begin is that there are only 60 cable vessels around. (Take a look at them here.) It’s a good thing that these scruffy-looking ships exist; indeed, without them the internet would not operate. But not only are the cable ships few in number—they’re also getting on in years. As Dan Swinhoe reports for DCD Magazine, no new cable ships were delivered between 2004 and 2010, and only five ships were delivered between 2011 and 2020. “Only eight of those 60 ships are younger than 18, with most between 20 and 30 years old. 19 are over 30 years old, and one is over 50,” Swinhoe notes. Like the world’s undersea cables, the cable ships are privately owned—and the market, as of yet, seems to have no interest in improving things. This might be a chance for governments—especially the world’s predominant naval powers, such as the United States—to step in. Alternatively, cable operators, which include not just telecommunications firms but tech giants like Google, too, might want to buy their own cable ships.

In the future, more submarine cables will be placed underneath the seabed to make them less exposed to damage—but that, too, depends on the 60 cable ships being available. If Chinese fishing and cargo vessels want to accidentally damage or sever the 15 undersea cables connecting Taiwan to the rest of the world, the near future thus offers enticing prospects. Indeed, given the world’s dependence on the cables and the few ships that can service them, the near future offers tempting prospects for any country ready to create a few more “accidents” at sea.

Cable sabotage could become our era’s blockade—and unlike past generations’ blockades, it can be conducted on the sly. No wonder other telecom operators are studying CHT’s backup operations, because they, too, could be forced to deploy such measures, in Taiwan and beyond. And let’s hope many countries study Taiwan’s response. Responding to a devastating but invisible blockade could become one of the thorniest diplomatic challenges facing Western governments.