NATO’s Below-Water Blind Spot: Why the Alliance Is Racing to Protect the Seabed — and Why It Started Too Late
The Nord Stream pipelines were blown up on September 26, 2022. Three of four lines destroyed in coordinated explosions on the Baltic seabed. The largest single release of methane in recorded history. And for nearly two years afterward, NATO did almost nothing about it.
Not nothing publicly — there were statements, expressions of concern, calls for investigation. But no doctrine, no mission, no dedicated capability to protect the millions of miles of cable and pipe that carry the world’s data, energy, and money across the ocean floor. The Alliance that had spent decades preparing for a tank war on the European plain had simply not thought about what happens 200 meters below its ships.
That is now changing. But whether the change is happening fast enough — or whether the gap between vulnerability and response has grown too wide — is an open question.
The Soft Underbelly of Western Power
The numbers are stark. About 97 percent of the world’s intercontinental telecommunications travel through undersea cables. Nearly a million miles of fiber optic line, laid across the seabed over decades, carries everything from bank transfers to military communications. More than four-fifths of US military communications flow through these privately owned cables. Aaron Bateman of George Washington University has called them the “soft underbelly” of American global power — and he is right.
Energy infrastructure is equally exposed. The Nord Stream attack demonstrated that a pipeline can be destroyed with a few hundred kilograms of explosives placed at the right depth. The Balticconnector pipeline between Finland and Estonia was damaged in October 2023. The Estlink 2 power cable connecting the same two countries was cut in December 2024, along with four telecom lines. A Finnish court later dismissed the case against the crew of the seized Eagle S tanker, citing a lack of clear evidence. That outcome was convenient for whoever did the cutting.
The total known incidents in the Baltic now exceed 44. And the Baltic is just one theater. Four cables were cut in the Red Sea in March 2024, disrupting a quarter of data traffic between Asia and Europe. The proximate cause — a sinking ship’s anchor dragged across the seabed — was itself the product of a broader conflict. But the vulnerability is universal.
Russia’s Underwater Arsenal
Russia has been preparing for this fight for decades. The Main Directorate of Deep-Sea Research, known by its Russian acronym GUGI, operates around 50 vessels built for deep-water operations. This is a separate command within the Russian Ministry of Defense, distinct from the navy, and its capabilities are not theoretical.
The spy ship Yantar, equipped with submersibles and robotic arms capable of diving to 6,000 meters, has been tracked loitering over cables linking Ireland to the UK, mapping cables off Svalbard and Norway, and patrolling the Irish Sea where three key cables connect Ireland to Britain. Moscow calls it a research vessel. NATO intelligence calls it a sabotage platform waiting for orders.
GUGI also operates submarines that can dive to 2,500-3,000 meters — deep enough to reach virtually any cable in the world. In April 2026, British and Norwegian authorities announced they had foiled a Russian submarine plot to survey undersea cables in the North Atlantic. The operation was detected and interdicted, but the fact that it happened at all — that a Russian submarine was caught positioning itself over critical NATO cable infrastructure — should silence anyone who still thinks this is theory.
Russian doctrine is explicit on this point. Targeting undersea infrastructure is understood in Moscow as a way to weaken the “will to fight” in the West without triggering a conventional military response. It is hybrid warfare in its purest form: a cheap, deniable attack on the infrastructure that makes modern life function, delivered through the ambiguity of the high seas.
And China is watching. Beijing has tested a new experimental device capable of cutting cables at depths of thousands of meters. If the current dynamic holds, the West will soon face two adversaries capable of severing its data lifelines, not one.
A Belated Awakening
NATO’s response has been real but reactive. The Alliance established the Centre for Security of Critical Undersea Infrastructure in 2024. In January 2025, it launched Baltic Sentry, a multi-domain mission deploying frigates, maritime patrol aircraft, and naval drones to monitor the Baltic Sea. In June 2025, the experimental Task Force X began work on building a common operating picture for undersea threats. NATO has also created a Critical Undersea Infrastructure Network to coordinate with private industry operators.
The European Union, for its part, announced a 1 billion euro Cable Security Action Plan in February 2025, including a reserve of emergency repair vessels. In February 2026, it adopted a Cable Security Toolbox with 347 million euros in dedicated projects. Finland has begun detaining suspect vessels — the Fitburg was boarded by special forces on New Year’s Eve 2025 after dragging its anchor across a cable linking Helsinki to Tallinn.
Even the US Navy has gotten into the act, surfacing an Astute-class nuclear attack submarine in a deliberate show of underwater presence — a signal to Moscow that undersea operations are being watched.
All of this is welcome. All of it is late.
The Gap That Remains
The problem is not that NATO is doing nothing. The problem is that the response has been tactical rather than strategic — a series of initiatives bolted onto existing structures rather than a fundamental reassessment of what it means to secure the ocean floor.
Consider the attribution problem. When a cable is cut, who did it? The ships involved fly flags of convenience, change names every few months, and are crewed by multinationals with no loyalty to any flag. The Fitburg was Korean-built, Romanian-flagged, Turkish-owned, sailing between Russia and Israel with a crew of Georgians and Kazakhs. The Eagle S was part of the “ghost fleet” — up to 600 vessels Russia uses to evade oil sanctions. A Finnish court could not attribute the Estlink 2 damage to anyone, despite the ship’s Russian origins and the Kremlin’s obvious motive.
This is not an accident. It is the strategy. Russia relies on what the War on the Rocks analysts call “deniability” — the ability to inflict damage that everyone suspects but no one can prove. NATO’s response has been to try to “deny the deniability” through better monitoring, more sensors, and a shared operational picture. But sensors do not solve the legal problem. And they do not solve the attribution problem. A camera on the seabed can show a ship dragging its anchor over a cable. It cannot prove that the anchor was dragged deliberately rather than through negligence — and it certainly cannot prove that the order came from Moscow.
The second gap is scale. The Baltic is a shallow, contained sea — relatively easy to monitor compared to the Atlantic, the Pacific, or the Mediterranean. The NATO members surrounding it are wealthy, technologically advanced, and newly motivated by the addition of Finland and Sweden to the Alliance. But what happens in the Greenland-Iceland-UK gap, where Russian submarines can slip into the Atlantic undetected? What happens in the South China Sea, where Chinese vessels have already been documented approaching cable routes?
The third gap is the simplest and the hardest to close: the cables are privately owned. Tech and energy companies laid them, maintain them, and own them. NATO can patrol the surface, but it cannot guard 1 million miles of fiber optic line. It cannot station a frigate over every cable junction. The vulnerability is structural, built into the architecture of the global economy itself.
The Øresund Strait and the Shape of Things to Come
The Øresund Strait between Sweden and Denmark is now one of the flashpoints of this conflict. Every vessel entering or leaving the Baltic passes through this 2.5-mile corridor. In 2025, Nordic authorities verified 292 vessels linked to Russia transiting the strait. At least some of them carried armed contractors — personnel linked to paramilitary companies with Kremlin ties.
NATO foreign ministers met in Helsingborg last week, looking out over waters that have become the front line of a war that is not a war. There are no battleships exchanging fire. There are no declared combatants. There are just cables breaking, ships with murky ownership dragging their anchors, and an intelligence community struggling to piece together who did what.
This is the shape of 21st-century conflict below the surface. It is cheap. It is deniable. And it targets the infrastructure that 21st-century life cannot function without.
NATO has begun to wake up to this reality. Baltic Sentry patrols the sea. Task Force X builds the data picture. Finland boards suspect ships. The EU funds repair capacity. These are not nothing. But they are responses to a problem that has been building for years — and that will only accelerate.
The question is not whether Russia will cut another cable. It is whether the Alliance can build a deterrent before the next attack — and before the one after that — demonstrates how much of modern life can be disrupted by a few men in a submersible with a pair of hydraulic shears.