Cable Wars in the Deep

As tensions simmer in the Taiwan Strait yet again, the battle for undersea cables signals a new front in the geopolitical brinkmanship between China and Taiwan.

In the contest for Taiwan’s future, China has mastered the art of subtle yet insidious pressure. From balloon overflights to sand dredging, the Chinese Communist Party (CCP) has perfected aggressive ‘grey zone’ tactics. The latest manifestation of this strategy has surfaced, quite literally, in the waters of the Taiwan Strait, where repeated damage to undersea communication cables has heightened fears of Chinese sabotage.

The Taiwan Straits has long been a geopolitical powder keg with its 110-mile breadth separating a self-governing democracy from an authoritarian giant that claims it as its own. Taiwan’s economic and strategic vitality hinges on a web of undersea cables connecting it to the world. Disrupting these cables is a calculated form of hybrid warfare to test Taiwan’s resilience.

The latest episode unfolded this week when Taiwan’s coast guard intercepted a Togolese-flagged cargo ship after a key undersea cable linking the main island to the Penghu archipelago was mysteriously severed. The ship, reportedly financed by China and staffed exclusively by Chinese nationals, had dropped anchor alarmingly close to the cable before communications were cut. Though Beijing dismissed Taiwan’s claims as political manipulation, Taipei pointed to a broader pattern of similar disruptions in recent years.

In early 2023, two cables near Taiwan’s Matsu Islands, critical links between the island and its outposts, were severed within a week. Taiwanese officials identified Chinese vessels as the culprits but stopped short of officially blaming Beijing. More recently, a China-owned, Cameroon-registered vessel was suspected of damaging another cable leading to the United States. Taiwan now maintains a watchlist of over 50 ships believed to be operating under “flags of convenience” - an obfuscation tactic allowing Chinese firms to avoid direct association with the CCP while operating in contested waters.

China’s denials are predictable, but follow a pattern of maritime intimidation. Beijing’s ‘grey zone’ operations, which fall below the threshold of conventional military aggression, extend beyond undersea sabotage. Chinese coast guard patrols near Taiwan’s Kinmen Islands (territory controlled by Taipei but located perilously close to China’s Fujian province) have intensified. These so-called ‘law enforcement’ operations, occurring four times a month on average, are seen by Taiwan as deliberate harassment aimed at undermining its sovereignty.

The cable disruptions have also drawn uncomfortable parallels to events in the Baltic Sea. Following Russia’s invasion of Ukraine, several undersea cables and gas pipelines were mysteriously damaged, with Moscow emerging as the prime suspect. Like Taiwan, NATO members feared these incidents were trial runs for more aggressive hybrid warfare tactics.

Why does China care so much about Taiwan’s undersea cables? The answer lies in Beijing’s long-term strategy. By interfering with communications infrastructure, China signals its ability to sever Taiwan’s lifeline in the event of a conflict. The cables are crucial not just for internet access but also for financial markets, military coordination, and government communications. In a full-scale blockade scenario - one of Beijing’s most likely invasion strategies - Taiwan’s isolation would begin with the snipping of these fiber-optic arteries.

Taipei is responding with vigilance. The government has ramped up patrols, fortified its monitoring of suspect vessels and pushed for greater international awareness. Yet, as tensions rise, so does the risk of miscalculation.

Undersea cables have long been a battleground in modern geopolitics. During the Cold War, the United States and the Soviet Union engaged in deep-sea espionage, tapping each other’s communication lines. Today, a new version of that contest is playing out in the Taiwan Strait. The difference now is that China’s goal is not merely surveillance but disruption, coercion and ultimately, dominance.

If Beijing is testing the limits of what it can get away with, Taiwan’s response will set a precedent. The next phase of the island’s struggle for sovereignty may not be fought in the air or on land, but the murky depths of the sea.