The world's undersea cable network spans roughly 1.4 million kilometers (870,000 miles) and carries over 95% of intercontinental internet traffic, yet it remains vulnerable to accidental damage, such as ship anchors, and deliberate disruption.

Recent incidents in the Baltic Sea and Red Sea have underscored the cables' fragility. Policymakers are now staging international initiatives to safeguard the system.

"We need to work together to defend the entire network," Singaporean Defense Minister Chan Chun Sing said at the IISS Shangri-La Dialogue, Asia's premier security forum, earlier this month.

"There's no point trying to defend the integrity and security of a submarine cable by looking at a point. We need both ends to be secure," he added.

NATO nations patrol Baltic Sea as cables fail

In February 2024, multiple cables in the Red Sea were severed when anchors from a cargo vessel sunk by Houthi militants dragged along the seabed. The damage caused a sharp reduction in internet capacity between Europe and Asia, disrupting everything from financial transactions to video conferencing.

Meanwhile, Europe has struggled with a series of similar faults in the Baltic Sea, with many Western officials hinting those cables were intentionally damaged by ships linked to Russia. Experts have warned, however, that there has been no proof of deliberate damage.

Since January, some NATO members have expanded the deployment of frigates, maritime patrol aircraft and naval drones to conduct regular cable-surveillance missions across vital waterways.

Beijing using cable projects as leverage in naval disputes

In Southeast Asia, subsea infrastructure also faces similar geopolitical friction. In February, Taiwanese officials detained a Chinese-crewed ship after an undersea communications cable was damaged near the self-ruled island, which China sees as a breakaway province. China has also increasingly pressured cable consortia laying new links from Japan through the South China Sea to seek Beijing's "permission," effectively doubling down on its claims in internationally disputed waters.

"This is just another way that China is trying to assert its sovereignty over the South China Sea," Zachary Abuza, professor at the National War College in Washington, told DW.

China is also reportedly developing "advanced cable-cutting devices capable of targeting armored cables at unprecedented depths," according to a commentary published by Tokyo-based magazine Nikkei Asia this week.

Southeast Asian nations are also worried about the cables being threatened by natural disasters and possibly costing them access to new and expanded renewable energy projects, such as offshore wind farms.

According to Nikkei Asia, investment in the submarine power cable sector is projected to reach $1.95 billion (€1.70) by 2030.

Hanoi 'cautious not to anger China'

Vietnam, a nation of 90 million people served by just five undersea cables, lost up to 75% of its data capacity in February 2023 when all five suffered partial or total damage. In June last year, three of the five submarine internet cables failed again.

The cause for those disruptions is still unclear, at least officially. Alexander Vuving, a professor at the Daniel K. Inouye Asia-Pacific Center for Security Studies in Honolulu, told DW that Hanoi is "cautious not to anger China and tends to dismiss the suspicion that the cables were intentionally damaged."

"They argue that the cables are located in one of the world's busiest shipping routes, hence the chance that fishing vessels unintentionally damage them is high," Vuving added.

"However, this argument leaves unanswered the question of why the rate of incidents rose sharply in recent years."

EU as a way out of US-China clinch

Vietnam wants to add up to four new cables in the coming years to significantly boost connectivity speeds and the power supply, as the country looks to progress into higher-end, tech manufacturing.

Hanoi has encouraged Vietnamese telecom companies to spearhead this move. However, laying cables across the ocean floor is costly, and Vietnamese firms are looking for outside investment, mainly from China and the US.

"Many in Vietnam see this as a no-win situation as they do not want to be dependent on either China or the US and certainly do not want to get entangled in the US-China competition," said Vuving.

"European companies can help Vietnam escape this catch-22 situation. The same can be said regarding other countries in Southeast Asia."

Brussels working on 'cable diplomacy'

France's Alcatel Submarine Networks is often regarded as the global leader in subsea cable installation, and several European firms operate sizable fleets of cable repair ships.

In February, the EU published its Cable Security Action plan, which called on Brussels to "develop and deploy an advanced cable diplomacy."

"When it comes to addressing incidents," the plan reads, "the [EU] should enhance the exchange of information with, for instance, Indo Pacific partners who are facing similar incidents in relation to critical submarine infrastructures."

Soon thereafter, Henna Virkkunen, the European Commission's executive vice president in charge of tech sovereignty and security, announced that almost €1 billion would be redirected in the EU's budget to boost surveillance of undersea cables and establish a fleet of emergency repair vessels.

Does US want Europeans in Asia?

Whether Europe is actually capable of supporting Asia is another matter.

"While Europeans could help build more undersea cable architecture for Southeast Asia, China already dominates the undersea cable network in the region," Joshua Kurlantzick, senior fellow for Southeast Asia at the Council on Foreign Relations, told DW.

"It would take a massive and very costly effort by Europe to come anywhere near supplanting China's cable network, and I don't think Europe can afford that," he added.

Moreover, there could be pushback from the US, which appears to increasingly believe that Europeans should disengage from the Indo-Pacific region.

Speaking at the Shangri-La Dialogue summit, US Defense Secretary Pete Hegseth argued that European states should limit their engagement and investments in regions like Southeast Asia to focus entirely on safeguarding Europe.

Kaja Kallas, the EU's foreign policy chief, pushed back a day later, arguing that "it's an illusion that these security theaters of Indo-Pacific and Europe are not interlinked."

She called for Europe and Asia to collaborate against covert "shadow fleets" and review maritime security laws to protect submarine cable networks.

Edited by: Darko Janjevic