Undersea cables face rising sabotage risk, analysts warn

Global seabed infrastructure faces a growing sabotage risk, with analysts warning that undersea cables, landing stations and other systems have become increasingly attractive targets for state-backed covert operations. Recent incidents — including damaged cables near Taiwan, in the Baltic Sea and off Norway — have raised concerns about “gray-zone” tactics, where Chinese merchant vessels may act on Russia’s behalf.

Undersea fiber optic cables transmit most intercontinental traffic, including an estimated $10 trillion in daily financial transactions, according to the U.S. Naval Institute and research cited by the Office of the Director of National Intelligence.

Roughly 20,000 miles of subsea pipelines also move oil and gas across oceans.

How has the threat changed?

Advances in technology have made once-protected infrastructure accessible to more actors. Commercial vessels with modified equipment, along with manned and unmanned deep-diving submersibles, can now reach cables and pipelines at greater depths.

Analysts note that political motives, relatively low costs and limited repercussions increase the incentive for sabotage.

Investigations have documented damage to telecommunications cables near Taiwan, in the Baltic Sea and off Norway. Vessel-tracking data placed Chinese or Russian-flagged ships in the area before several breaks. Chinese officials have said at least one case was accidental.

What patents show possible capability?

A 2020 filing by Lishui University described a “dragging type submarine cable cutting device” designed to sever cables quickly and cheaply. A 2009 application from engineers at China’s State Oceanic Administration’s South China Sea branch outlined a similar anchor-shaped cutter.

While there is no evidence that these devices were deployed, marine experts told Newsweek that their existence illustrates available technical options.

Experts say commercial ships used in covert operations — often described as hybrid or gray-zone activity — can help conceal responsibility while threatening critical systems.

Why is protection difficult?

Samuel Byers, senior national security adviser at the Center for Maritime Strategy, said the complexity and cost of reaching seabed assets are decreasing.

“What you once needed a billion-dollar submarine for can now be accomplished with an operation you can put together for a hundred million dollars or so,” Byers said.

U.S. and allied fleets cannot continuously guard the estimated 750,000 miles of undersea cables worldwide, and naval forces already have other missions. Analysts say monitoring may have to focus on chokepoints where multiple systems converge, such as the Malacca Strait and Bab-el-Mandeb.

The Atlantic Council has reported that state influence over cable companies can shape routes and embed weaknesses. Internet-based remote management systems monitor cable health but also open the door to cyberattacks. Onshore landing stations, where cables connect to land networks, remain high-value physical targets.

What do experts recommend?

Suggested measures include expanding offshore and satellite surveillance, deploying more unmanned patrol systems and increasing allied coordination. Some analysts also say deterrence should include non-maritime responses to raise the penalties for sabotage.

“It is vital that global democracies mount a significant response to deter future attempts by Russia and China to disrupt Western critical subsea infrastructure,” said Benjamin L. Schmitt, senior fellow at the University of Pennsylvania. Without stronger action, he and others warn, such attacks are likely to grow.