The internet is often pictured as wireless and weightless, but international connectivity is overwhelmingly physical. Hair-thin optical fibers, protected inside cables laid across seabeds, carry cloud traffic, financial messages, video calls, government communications, and ordinary web requests between continents. Satellites are valuable for remote coverage and resilience, yet they do not replace the enormous capacity and low unit cost of undersea fiber.
The International Telecommunication Union says submarine telecommunications cables facilitate “over 99% of international data exchange.” In February 2025, it described a network of about 500 cables spanning more than 1.7 million kilometers (ITU). Those aggregate figures can obscure concentration: countries may depend on a handful of landing stations, islands may have only one or two routes, and several nominally separate cables can pass through the same narrow corridor.
A cable is engineered for hostile conditions but not immunity. Earthquakes and undersea landslides can sever multiple systems. Fishing gear and anchors cause frequent accidental damage in shallower water. The ITU’s 2025 connectivity analysis attributed 86 percent of faults to human activities such as fishing and anchoring, and reported more than 500 operational systems totaling roughly 1.4 million kilometers under its counting method (ITU). Different totals reflect whether planned systems and route measures are included, which is why policymakers should treat cable statistics as defined estimates rather than a single permanent count.
Breaks are routine enough that repair, not perfect prevention, is the foundation of resilience. The ITU and International Cable Protection Committee reported more than 200 repairs worldwide in 2023—over three each week on average (ITU). Specialized ships must locate a fault, recover the cable from depth, splice it, test it, and return it to the seabed. Weather, permits, port access, customs, spare parts, and the availability of a repair vessel can turn a technical job into a policy bottleneck.
Networks usually route around a single failure, but redundancy is not the same as diversity. Two cables owned by different consortia may share a landing site, power supply, terrestrial backhaul, or seabed path. Capacity may exist on an alternative route but not under the right commercial agreement. Good resilience mapping therefore asks whether paths fail independently and whether traffic can actually move when they do. Exercises should include simultaneous faults and loss of the terrestrial links that connect landing stations to data centers.
Ownership is also changing. The ITU says annual cable investment grew from about $0.8 billion in 2015 to $9.7 billion in 2025, with hyperscale technology companies playing a leading role. Direct investment by large cloud and content providers can add capacity and new routes, but it also joins infrastructure control to the economics of a few global platforms. Governments must distinguish legitimate security review from protectionism and maintain predictable landing, maintenance, and repair rules.
Security has risen alongside resilience. Deliberate damage, covert access, compromised network-management systems, and pressure on suppliers require different responses from accidental anchor strikes. The FCC modernized its U.S. cable-landing framework in 2025; at that time, it counted 91 licensed cable systems owned by approximately 147 unique licensees and sought more standardized cybersecurity and physical-security requirements (FCC). Effective oversight should cover operators and landing facilities while protecting sensitive route and vulnerability information.
Europe has adopted a broader cycle of prevention, detection, response and repair, and deterrence. In February 2026, the European Commission proposed a cable-security toolbox, priority projects, and a €347 million investment package following an EU-wide risk assessment and stress-test guidance (European Commission). The emphasis on funding and coordination matters: a mandate to diversify routes accomplishes little if low-income or geographically difficult regions cannot finance a new landing.
International cooperation is unavoidable because cables cross maritime zones, land in multiple jurisdictions, and serve traffic far beyond their endpoints. The ITU and ICPC created an International Advisory Body for Submarine Cable Resilience in November 2024 to address timely licensing and repair, physical-damage risk, continuity, and cross-border collaboration. Its three working groups had more than 160 expert members by 2025 (ITU).
The central policy lesson is mundane but consequential: resilience comes from spare capacity, geographically independent routes, practiced restoration, repair ships, compatible permits, and trusted information sharing. Undersea cables are hidden from most users precisely because this system usually works. Keeping it that way requires treating an ocean-spanning industrial network as core public infrastructure, even when most of its assets are privately financed and operated.