With all the craziness of the last six weeks, it’s easy to become enraptured by all the “glitz-bang-pow“, and to lose track of the truly important things…like internet access, for example.
Much of the crucial digital lifelines of the modern global economy lie largely unseen and unprotected beneath the oceans. Submarine cables — bundled fiber-optic threads wrapped in layers of protective materials — carry an estimated 99% of international data traffic, representing an estimated $10 trillion in daily financial transactions. Clearly, these cables are vital components of any national infrastructure…and, just as clearly, they are very high-priority targets in any war scenario. Despite their critical importance, these cables remain surprisingly vulnerable to both accidental damage and deliberate sabotage, creating an asymmetric vulnerability that security experts increasingly view as a critical national security concern.
Recent incidents have highlighted this vulnerability. In late 2023, and again in late 2024, multiple cables in the Baltic Sea were damaged within weeks of each other, including the Svalbard cable connecting Norway’s remote Arctic research station to the mainland. While officials initially cited “technical problems,” subsequent investigations pointed to deliberate actions, with suspicion falling on Russian vessels that had been tracked in proximity to the damaged sections. Similar incidents have occurred in the Mediterranean and Red Sea, where the timing and pattern of damage suggested coordinated action rather than accidental encounters with ship anchors or fishing equipment…which, given the immediate impacts, should be surprising to no one, as the war in Ukraine continues to rage.
The security implications extend far beyond temporary internet disruptions. Major financial centers like London, New York, and Singapore depend on millisecond-level transmission speeds for trading operations, with even brief outages potentially causing billions in economic damage. Military communications, intelligence sharing between allies, and diplomatic channels all rely on these same physical pathways, creating a strategic vulnerability that potential adversaries have clearly recognized.
Unlike traditional military targets, undersea cables present adversaries with an ideal gray-zone target. Damage can be plausibly denied as accidental, attribution is extremely difficult, and repairs can take weeks depending on the location and conditions. This provides hostile actors with the ability to cause significant disruption while remaining below the threshold of activities that would trigger conventional military responses.
The technical challenge of defending these cables is substantial. The global submarine cable network spans over 750,000 miles, often in international waters beyond territorial jurisdiction. Cable routes are publicly documented for maritime safety, making their locations easily accessible to potential saboteurs. Monitoring such vast distances presents an almost impossible surveillance challenge, especially in deep ocean areas where depths exceed 3,000 meters.
Of course, this has been happening since undersea cables were first laid in the 19th Century, most notably when the United States cut Spanish telegraph cables in both Cuba and the Philippines theaters of the Spanish-American War. During World War I, one of Britain’s first and most significant strategic moves came just hours after declaring war in August 1914, when the cable ship “CS Alert” severed Germany’s five transatlantic cables near the English Channel. This operation, codenamed Operation Telekom, effectively cut Germany’s direct communication links with the Americas and much of the world. Britain simultaneously took control of most neutral cable stations, forcing German diplomatic and military communications onto easily intercepted wireless channels or through cables that passed through British-controlled territory.
The British established “Room 40“, a specialized naval intelligence unit that interceded and decoded German messages, providing critical intelligence. The most famous success came with the interception and decryption of the Zimmermann Telegram in 1917, which revealed Germany’s attempt to entice Mexico into attacking the United States — a diplomatic catastrophe that helped bring America into the war.
In World War II, Britain expanded these capabilities with Operation ‘Cutting’. The Royal Navy again targeted German undersea cables, but added sophisticated tapping operations. Combined with the codebreaking work at Bletchley Park, these undersea operations provided crucial intelligence on German naval movements, particularly U-boat operations, significantly contributing to Allied victory in the Battle of the Atlantic.
Modern cable attacks no longer require crude methods like physical cutting. Advanced submersibles can quickly and silently install tapping devices without severing cables, allowing for collection without detection. Both the Russian and Chinese navies are known to operate specialized submarines and surface ships equipped for undersea operations near critical cable infrastructure, including the Yantar, a Russian “research vessel” observed loitering near critical cable junctions in the Atlantic.
These strategic vulnerabilities are magnified by the concentration of key connection points. Cable landing stations — where submarine cables connect to terrestrial networks — represent critical sea-based chokepoints, with certain locations in Egypt, Malaysia, and Sicily serving as hubs for dozens of major cables. A modern, coordinated attack on multiple landing stations could severely disrupt global connectivity in ways that would overwhelm the limited redundancy built into the system.
Despite the growing awareness of these vulnerabilities, international legal protections remain inadequate. The 1884 Convention for the Protection of Submarine Telegraph Cables provides limited safeguards, while the UN Convention on the Law of the Sea only offers general provisions against deliberate damage. Enforcement mechanisms are virtually non-existent in international waters, creating a legal gray zone that mirrors the operational one.
As tensions rise between major powers, enhancing resilience against cable disruption has become an urgent security priority. Proposed measures include increased naval patrols near critical infrastructure, enhanced monitoring through seabed sensors, diversification of cable routes, and hardening of physical infrastructure. However, the scale of the challenge means complete protection remains impossible, leaving this critical infrastructure as a persistent vulnerability in an increasingly contested global environment.
One thing people frequently fail to understand – an outgrowth of the increasing sociological separation of the civilian and military spheres – is that naval warfare is far more than dramatic gun battles at sea, determined amphibious assaults, and exciting launches of fighter planes from the decks of aircraft carriers.”War“, as such, has been a term too frequently applied outside of its true domain, diluting public understanding of its implications: Sure, “war” is scary and destructive in general, but there are plenty of avenues of attack that are certainly not part of the ‘war on poverty’. This is why the Imperial Japanese Navy shelled a beach in Santa Barbara, California in 1942…which came as a hell of a surprise to local residents, and which had some very unforeseen consequences that succeeded in damaging the United States – not enough to win the war, but enough to instill distrust, the more people thought about it.
People concerned for not only their physical, but financial, security, need to start relearning how militaries think, because while the civilian may not care much about warfare, warfare cares very much about you.
