September 04, 2025

How the U.S. Should Push the Quad-Plus to Protect Undersea Cables

By: Ryan Claffey

This article was originally published in Breaking Defense.

Subsea cables facilitate the flow of over 99 percent of global internet traffic and $10 trillion in daily financial transactions. They are the unseen arteries of intercontinental communication and commerce—the physical manifestation of the internet. And right now, they’re under attack.

While, on average, subsea cables suffer from accidental faults once every other day, recent high-profile incidents point to a troubling pattern of deliberate subsea sabotage—acts made harder to trace as Russia and China deploy thousands of older, foreign-flagged vessels to obscure attribution. Nowhere is the threat of subsea sabotage more acute than around Taiwan.

Subsea sabotage marks a new era in gray zone warfare, and the United States and its partners have a narrow window to expose and confront this threat before it becomes the new normal.

In early 2023, Chinese vessels were blamed for cutting the only two cables connecting Taiwan’s Matsu Islands to Formosa, leaving 14,000 residents reliant on microwave radio transmission for six weeks.

China continues to refine its tactics to obscure attribution and evade accountability. In January, the Chinese-owned, Cameroonian-flagged cargo ship Shunxing 39 reportedly damaged a subsea cable near Keelung, Taiwan. The vessel switched off its identification signal while passing over the cable, severed it, and reappeared as the Tanzanian-flagged Xingshun 39 — an apparent attempt to confuse attribution, according to widespread media reports and statements from the Taiwanese government.

Read the full article on Breaking Defense.

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