Pacific undersea cables risk has moved up the security agenda, after two recent reports warned that the digital links carrying almost all international communications across the Pacific are more exposed to sabotage than previously assumed. An index by the China Strategic Risks Institute identified ten trans-Pacific cables at particularly high risk, with the danger highest around Taiwan, Japan and the Philippines.
The cables matter because they carry about 99 percent of international communications, according to the daily briefing 10 Things Global News, which highlighted the issue on November 2. A major failure on a single trans-Pacific line could overwhelm available capacity on direct routes between the United States, Taiwan, Japan and the Philippines, forcing data onto slower, less direct routes, the report’s authors warned. Several of the ten most vulnerable cables are still under development and have significant United States corporate ownership.
Which cables are most exposed
Google’s TPU project, Meta’s ORCA cable and the E2A cable, co-owned by Verizon alongside companies in Japan, South Korea and Taiwan, all landed in the top five of the institute’s risk scoring index, according to summaries of the report. Four of the ten highest-scoring cables are still under construction, the report found, which means decisions about routing, protection and ownership are still being made while the risk picture is becoming clearer.
Geography concentrates the danger. Subsea cables connecting the region with the United States must pass through shallow waters and busy shipping lanes, where a dragged anchor can pass for an accident, the report noted. Cables score higher in the index if they land in Taiwan or cross waters Beijing claims, and shallow, crowded lanes add further risk. The Philippines faces a particular pinch: losing either of its direct links to Guam, which is tied to the United States mainland by only two direct cables, could leave almost no margin even with every spare fibre pair switched on, researchers found.
Research vessels and dual-use tools
A separate October 2026 report by the Center for Strategic and International Studies (CSIS) in Washington found that China-flagged research ships stood out as outliers in the time spent near subsea infrastructure, after analysing more than 200 research ships from several countries between 2020 and 2025. Philippine authorities said a Chinese vessel surveyed waters near the Batanes Islands without permission in September, accompanied by two Chinese coast guard ships, according to the November 2 briefing.
The institute’s report also identified dual-use tools that could reach cables in deep water once considered out of range, including a 4,000-metre-class cutting device from a research centre linked to China’s state shipbuilder. Beijing has not been accused in these reports of cutting a specific cable, and Chinese officials have described related naval activity as routine training. The reports’ warning is narrower but still stark: the tools, the geography and the traffic patterns now exist for a single incident — accidental or deliberate — to have outsized consequences for internet connectivity across the Pacific.
