Harmony: Russia’s new deep-sea surveillance web runs on Western tech

The detection network, called “Harmony”, appears to be an equivalent to the well-known SOSUS network that exists in the Greenland-Iceland-United Kingdom (GIUK) Gap. It is reportedly active in the Barents Sea and extends far beyond it.

Investigators believe some of its components may be located in the Baltic Sea, including near the site of the 1994 Estonia ferry disaster, where diving is prohibited as a memorial measure.

Russia acquired Western technology, including underwater antennas and drones, via shell companies based in Cyprus to build and expand the Harmony network.

Experts describe the system as part of Russia’s effort to establish an “underwater shield” to defend its Arctic bases and nuclear submarines. The sensors form an “invisible belt” stretching between Murmansk, Novaya Zemlya, and Franz Josef Land, designed to complicate the movement of NATO submarines and give the Kremlin an advantage in detecting and tracking undersea activity.

“The project is primarily defensive in nature — to protect nuclear capabilities and ports in the event of war — but it can also be used for offensive purposes,” said Alessio Patalano, a military analyst at King’s College London.

Investigators found that Russia began purchasing Western hydroacoustic surveillance systems in 2015, shortly after its annexation of Crimea, suggesting a long-term plan to militarize the Arctic and expand its strategic reach.

Amid these developments, UK Defense Secretary John Healey said that Russian submarine activity has returned to Cold War levels.

“This is further evidence of Russia’s growing aggression across Europe — not just against Ukraine,” he said.