Insights

Subsea cable fault happens from time to time in the world. On an average, there are approximately 200 faults per year on global subsea cable systems. Fishing and anchoring incidents account for 86% of the subsea cable faults.

According to Global Cable Repair Data Analysis 2024 & 2025, presented at SubOptic 2024 & SubOptic 2025 by Andy Palmer-Felgate, a member of the International Cable Protection Committee (ICPC) and Meta, there are 199 subsea cable faults each year from 2010-2024 on an average. The numbers of faults remain steady from 2013-2024, around 200 faults per year in the world, despite a 50% increase in subsea cable route mileage from 1.5 million to 2.7 million kilometers today. There is remarkable decrease on the fault per year per mileage. The achievement is a combination of better geophysical surveys, better armored cables, ability to do deeper burials, better public awareness of where the cables are located, and a higher premium placed in design on reliability.

With respect to the reason of fault, fishing and anchoring incidents account for 86% of the subsea cable faults, with details including:

• 44% out of suspected fishing or anchoring (unspecified);
• 28% out of fishing;
• 14% out of anchoring;
• 7% out of geological event;
• 4% out of abrasion; and
• 3% out of plant failure.

According to the ICPC, there were 206 repairs in 2023 in 136 jurisdictions with the longest repair taking 947 days. Analysis data contributions come from all major marine maintenance providers worldwide. The repairs are reported by their locality in a country’s Territorial Waters (TW), Exclusive Economic Zone (EEZ), or on the High Seas. Analysis shows 44% of repairs occurred in TW, 54% in the EEZ, and 2% in the High Seas.  Subsea cables are most vulnerable closer to shorelines in shallower waters. Repair response time more than doubled in 10 years for a variety of reasons.

On an average, the cost of repair is approximately $500,000 - $1 million per incident for subsea optic fiber cable and $10 million - $100 million per incident for subsea power cable, depending on many variables. For example, the repair of recent fault on the EstLink 2 electricity subsea cable between Finland and Estonia may cost €50 million to €60 million.  

In the past three years, there have been misinformation or concerns on deliberate sabotage of subsea cables. For example, multiple cable faults in the Baltic Sea and the Red Sea were misled to sabotage, turned out to be accidents after further investigation. According to the Washington Post, U.S. officials think that some recent Baltic cable faults were not intentional, but were instead “accidents caused by inexperienced crews serving aboard poorly maintained vessels.”

Sabotage of subsea infrastructure is rare in the world, but the September 2022 explosions of the Nord Stream 1 and 2 natural gas pipelines in the Baltic Sea have been concluded to be sabotaged after investigations. Any sabotage of critical infrastructure shall be condemned.

Severing a few cables intentionally won't have substantial harm to global data traffic, nor to that of a well-connected country. Reports by the RIPE NCC in Europe as well as Cloudflare and Kentik in the US show the damage of two cables in the Baltic Sea in November 2024 resulted in minimal impacts on Internet in the region. Even though, the security and resilience of subsea cable infrastructure is of strategic importance.  

The most effective measure for security and resilience of subsea cable infrastructure in the world is to improve the redundancy and diversity of subsea cable routes and encourage collaboration on various systems and stakeholders.