From the Baltic to the Pacific: Submarine Cable Security Threatened

A 2021 report by the online platform Total Telecom (Deutsche Welle Chinese) revealed that nearly 500 submarine cables run across the seabed, with a total length of 1.3 million kilometers. The number of submarine cables is now even greater.

Johannes Peters, head of the Center for Maritime Strategy and Security at Kiel University, said: "Global data exchange is all done through these cables. The internet, payment transfers, information transmission, and language messages are all done through these cables."

However, submarine communication networks are now threatened not only by natural aging but also by deliberate sabotage. Several incidents of submarine cable damage have occurred in the Baltic Sea. According to a study by the University of Washington in Seattle, 10 cables have been cut in the Baltic Sea since 2022, seven of which occurred between November 2024 and January 2025. A similar incident occurred again this summer.

Russia is considered a possible perpetrator. Traces of the anchor or unusual movements of the vessel reinforce this suspicion. However, to date, there is no conclusive evidence linking Moscow to the cause. Furthermore, it remains difficult to determine whether the damage was accidental, negligent, or intentional.

Chinese vessels are also involved. In November 2024, a Chinese cargo ship named " Yipeng 3 " was suspected. Sweden requested China's cooperation in the investigation.

Pacific submarine cables also raise concerns

In Asia, the security of submarine cables in the Pacific Ocean has also raised concerns among neighboring countries. These cables connect Japan, Taiwan, South Korea, and the United States.

This year, a Chinese expedient vessel named " Hongtai 58, " flying the Togolese flag, snagged an undersea cable near Taiwan, and its Chinese captain was convicted.

A report from the Center for Strategic and International Studies in Washington states that China has developed a vessel capable of cutting cables at a depth of 4,000 meters.

The U.S.-China Economic and Security Review Commission (USCC) wrote in its latest annual report to the U.S. Congress: "China is increasingly involved in cutting submarine cables as a means of exerting pressure in the gray area. At the same time, there are increasing indications that Beijing is developing new cable-cutting technologies that could be used in wartime."

Huge impact

Huang Sheng-hsiung, director of the Taiwan Network Information Center, stated that such an event would have a huge impact. "If the main power cable is damaged, the entire internet connection will be interrupted. An information vacuum will emerge in the affected areas." He warned that the impact would be particularly significant for Taiwan . "This would completely sever Taiwan 's connection with the outside world. This would not only affect communications but also many other sectors—such as education, the economy, the military, agriculture, and many more."

Peters of Kiel University stated that sabotaging submarine cables is not technically challenging. "You just need to let an anchor slide across the seabed, hook the cable, and then break it. You don't need a particularly powerful vessel."

Peters stated, "The Baltic Sea has now become a testing ground for hybrid naval warfare, and the rest of the world is watching closely."

How to protect yourself?

Huang Sheng-xiong stated that one of the countermeasures is to strengthen legal protection: enact laws to increase penalties for the deliberate cutting of submarine cables.

Technically, while a so-called "backup" can be implemented—using another undamaged cable to replace the data transmission—it is not a foolproof solution in the event of a military attack.

Therefore, countries around the Pacific are increasingly taking precautions. A report from the Center for Strategic and International Studies in Washington states that Japan and its allies are excluding Chinese companies from submarine cable projects involving US investment. Furthermore, Japan is also adopting a method of laying submarine cables with considerable spacing to prevent the entire system from being destroyed in the event of an attack.

Peters stated that, in addition, specific sea areas could be designated as areas where ships can only pass with special permission, in order to protect submarine cables there. "The cables themselves can also be protected using sensor technology."