Two Hundred Breaks a Year
Almost all of the internet's traffic between continents runs through glass fibres on the seabed. Every year 150 to 200 of those cables break. Very few of the breaks are sabotage. Most are caused by fishing gear and ship anchors.
That is roughly one every two days on a network of about 1.7 million km. The International Cable Protection Committee puts the yearly count at 150–200.
The cloud is mostly underwater
Satellites get the attention, but cables carry nearly everything that crosses a border.
Who carries U.S. international capacity
Whose traffic it is
Thick where it's dangerous, thin where it's quiet
Near shore a cable is armoured in steel and buried. In the deep ocean it is about as thick as a garden hose and simply rests on the seabed.
up to ~50 mm
~28 mm
~17–20 mm
The network grew. The breaks didn't.
Since 2014 the cable network has grown by about 70%, and traffic over it has tripled in four years. The number of faults has stayed about the same.
That means each kilometre now breaks less often: about 0.15–0.20 faults per 1,000 km in 2014, down to about 0.09–0.12 in 2025. *derived
Nets and anchors, not spies
Most faults happen in water shallower than 300 m, where trawlers work and ships drop anchor.
Causes of cable faults (ICPC)
Even in the headline cases
The 2024 Red Sea cuts were blamed on an anchor. The U.S. assessed that the Houthi-struck Rubymar dragged its anchor across three cables as it sank.
ICPC says it has no verified case of state-sponsored cable sabotage since the Second World War, and that deliberate damage makes up less than 1% of the total each year.
Where the breaks made the news
A few narrow straits and isolated islands depend on very few cables.
- Red Sea · Mar 20243 cables cut; anchor of sinking Rubymar blamed
- Tonga · Jan 2022eruption shredded ~80 km of cable; 38 days offline
- Baltic · Nov 20242 cables damaged; both fixed within 2 weeks
- Hormuz · 20265 segments; under 1% of world bandwidth
A small and ageing repair fleet
About 60 ships around the world can lay or fix cables, and they are spread across every ocean.
Tonga, 2022: how long an outage can last
What slows a repair down
Permits to work in a country's territorial waters can take a month or more. Bad weather can keep a ship in port, and every fault has to be found, grappled up and spliced on deck. Even the quick Baltic repairs in November 2024 took up to two weeks.
Look after the cables on the seabed
- Mariners and fishers: cable areas are printed in magenta on nautical charts. Don't anchor or trawl inside them.
- Check sabotage claims against the numbers: with 150–200 faults a year and under 1% deliberate, a single cut cable is usually an accident.
- Businesses: buy capacity on routes that don't share a chokepoint. Having more than one route is what keeps a fault from becoming an outage.
- Voters and policymakers: support funding for new repair ships and quicker repair permits. The fleet is ageing faster than the network is growing.
Sources & notes
- ICPC. International Cable Protection Committee, Media enquiries & factsheet (updated May 2026): ~150–200 faults/yr, stable; 70–80% from fishing & anchors; sabotage <1%; cable length ~1M km (2014) → ~1.7M km (2025); damage most common shallower than 300 m; Baltic Nov 2024 repairs; 5 segments through Hormuz, <1% of global bandwidth (TeleGeography analysis).
- TeleGeography FAQ. TeleGeography, Submarine Cable FAQs (2026): ~200 faults/yr on average (ICPC data); 600+ active & planned cables; 25-year design life; ‘garden hose’ width; satellites = 0.37% of U.S. international capacity (FCC statistics).
- TeleGeography 2025. TeleGeography, “How Many Submarine Cables Are There, Anyway?” (2025): 570 systems in service, 81 planned.
- TeleGeography bandwidth. TeleGeography, “Used International Bandwidth Reaches New Heights” (2025): 6.4 Pbps in 2024; tripled since 2020; growth 45% (2020) → 29% (2024); content & cloud ≈ three-quarters of demand.
- SubOptic / Infra-Analytics. TeleGeography & Infra-Analytics for SubOptic, “The Future of Submarine Cable Maintenance” (Jun 2025): ~⅔ of maintenance vessels at end of life by 2040; ~$3B over 15 years to renew the fleet (central estimate, as reported by Light Reading).
- Scientific American. Scientific American (2026), “Iran’s cable threats expose the aging fleet that repairs undersea internet cables”: ~60 cable-laying & maintenance ships, fewer than 20 repair-only; permits into territorial waters can take a month or more.
- UN World Ocean Assessment. United Nations, World Ocean Assessment, Ch. 19 “Submarine Cables and Pipelines” (after Carter et al. 2009): deep-sea cable ~17–20 mm; shelf cable ~28–50 mm with armour; burial typical to ~1,000–1,500 m depth.
- Reuters / AP (Tonga). Reuters & AP, Feb 2022: Tonga reconnected Feb 22, 2022 after the Jan 15 Hunga Tonga eruption tore up ~80 km of cable; repaired by CS Reliance (38 days).
- AP (Red Sea). Associated Press, Mar 2024: three Red Sea cables cut; U.S. assessed the anchor of the sinking, Houthi-struck Rubymar as the likely cause; ~14 cables run through the Red Sea.
- ≈2.1 Pbps for 2020 is DERIVED from TeleGeography’s “tripled since 2020” statement, not a published figure.
- Trend lines join two published endpoints; the straight segments between them are illustrative, not annual data.
- Faults per 1,000 km (≈0.15–0.20 in 2014 → ≈0.09–0.12 in 2025) is DERIVED by dividing ICPC fault and length figures.
- Map is schematic: magenta routes are illustrative, not the paths of real cables. Depth strip uses a square-root scale.
- Fault and cause statistics cover telecom cables; ICPC notes no global data exist for subsea power cables.