Despite the expansion of Starlink and other satellite services, the majority of the world’s internet traffic still travels through subsea cables crisscrossing the ocean floors. These cables, which coexist with oil and gas pipelines and submarine power cables, now face growing sabotage risks due to gray-zone warfare and open conflicts becoming more widespread.

The rising risks to the world’s invisible infrastructure beneath the waves are the main subject of a new book by Elisabeth Braw, titled ‘Undersea War’. Her book explores the modern rise in suspicious incidents where ships dragging their anchors have cut or damaged undersea cables and pipelines, from the Baltic Sea to the Pacific Ocean.

Braw acknowledges that about 60 percent of undersea cable damage is primarily due to human error during fishing and shipping activities, when weighted nets or anchors drag across the seabed. Natural hazards like storms and undersea landslides also account for a smaller proportion of such incidents. In total, between 150 and 200 cables are damaged each year and are usually repaired quickly.

However, international tension between superpowers and open war in Europe and the Middle East have led to increased scrutiny of cable-cutting incidents. Governments are investigating and sometimes prosecuting crews for allegedly causing deliberate damage to subsea cables. One notorious incident is the ‘Christmas Day massacre’ of 2024, when a Russian-linked oil tanker named Eagle S dragged its anchor for about 56 miles (90 kilometers), cutting or damaging four data cables and the Estlink 2 submarine power cable connecting the Baltic and Nordic power grids.

One of those data cables had also been severed by the Chinese cargo ship Yi Peng 3 just one month earlier in November 2024, when that ship damaged two data cables in the Baltic region. The ship’s crew was not prosecuted by European authorities, whereas the Finnish government attempted to prosecute three senior officers of the Eagle S.