The Financial Times published a major piece on the Russian oceanographic vessel Yantar—referred to in several Western reports as a “spy ship.” According to the paper, the vessel has raised concern in NATO capitals—links have been drawn to the possibility of damage to undersea cables, a threat to critical infrastructure that has been discussed for years. In the past year alone Yantar entered British territorial waters twice; Britain’s defence secretary John Healey publicly addressed Vladimir Putin, calling one incident “yet another example of mounting Russian aggression.”
The FT also describes a covert military unit that oversees the ship’s operations, and the measures NATO countries are taking to counter the threat; the paper suggests that Russia may be using Yantar to map vulnerable sections of the undersea cable network in advance of possible sabotage.
Yantar—An oceanographic research vessel of the Northern Fleet. Its operations are run by a secret unit of the Russian Ministry of Defence
The Main Directorate for Deep-Sea Research (GUGI) of the Russian Ministry of Defence was created in the heat of the Cold War. Since the 1960s the CIA has monitored its base at the settlement of Olenya Guba in the Murmansk region, on the shores of the Barents Sea.
According to the Financial Times, GUGI is “so secretive” that it operates apart from other armed services and reports directly to the Ministry of Defence. A former Northern Fleet officer says that by tasking the unit resembles military intelligence more than the navy: “By the work they do they have always been subordinate to the GRU,” he said, adding that the fleet limits itself to technical support because the unit’s facilities lie nearby.
In recent years the base at Olenya Guba has been significantly reinforced. Satellite imagery reveals a new barrier blocking the bay’s entrance and floating dry docks that are believed to be used to hide submarines from satellite observation. There is intense GPS jamming in the area—so severe that ordinary civilian ships heading north from Murmansk can lose tracking.
GUGI’s functions extend far beyond reconnaissance. The unit conducts sabotage in waters of potential adversaries, operates networks of Russian undersea sensors, detects foreign vessels in Russian waters and neutralises their equipment, such as hydroacoustic recording systems.
According to Siddharth Kaushal of the UK’s Royal United Services Institute, GUGI personnel possess “exceptional specialisation”: after five years of submarine service they undergo training based on the programme once designed for Soviet cosmonauts.
Even amid the war in Ukraine, the authorities continue to allocate significant resources to the unit, as evidenced by the commissioning of new intelligence vessels similar to Yantar. The FT reports that GUGI operates around 50 ships, including submarines and deep-diving vehicles, some capable of reaching depths of six kilometres.
“[GUGI] has invested heavily for many years and makes no secret of it,” notes defence analyst Pavel Luzin. In his view, the unit’s priorities in recent years have shifted from defensive tasks and fleet support to sabotage operations. In the summer of 2025 the UK imposed sanctions on GUGI.
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Yantar Is Outfitted With a Full Suite of Reconnaissance Equipment. It May Be Mapping NATO Countries’ Networks of Undersea Cables and Pipelines
According to the Financial Times, after Russia’s full-scale invasion of Ukraine in February 2022 Yantar went to sea only a limited number of times—three voyages of just over a month each and one lasting about seven weeks. The paper suggests that Russian authorities refrained from sending the vessel on longer missions because of sanctions or fears of escalating tensions with the West.
Only in November 2024 did the ship resume extended operations. Yantar then undertook a 97-day voyage along routes of critical infrastructure off Europe’s Atlantic coast. Journalists reached that conclusion by analysing satellite imagery and automatic identification system (AIS) data.
The vessel identified as Yantar traveled along two undersea cables linking Svalbard with Norway, and was also detected in the Irish Sea, where three key cables connect Ireland to the United Kingdom. According to the FT, the ship remained in the area for several hours before drawing the attention of the British military.
Journalists suggest that Yantar may have been tasked with mapping—and possibly intercepting data from—NATO undersea cables. The paper also notes that between October 2023 and November 2024 another ten Russian vessels were continuously present in British waters, including near the Irish coast.
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Undersea Cables Are Critical for Communications and Financial Transactions
Undersea infrastructure is becoming an increasingly vulnerable target for sabotage. Some 99% of the United Kingdom’s digital traffic flows through undersea cables, and up to 75% of gas supplies are transported by pipeline. Those cables sustain communications across NATO, including military channels, and are vital for financial transactions and international trade.
Vessels such as Yantar are equipped with deep-diving vehicles and tools that can tap into cables to intercept data or attach explosive devices. Western navies believe these ships likely identify key nodes where sabotage or attack would produce the greatest disruption.
Ireland is particularly vulnerable, not being a NATO member and traditionally relying on the United Kingdom and the United States for security. Dublin has already invested €60 million in an undersea sonar system to monitor its waters. London has stepped up patrols and is developing a seabed monitoring system known as the “Atlantic Bastion.” In addition, Britain and its allies take turns patrolling the strategically important Greenland–Iceland–UK gap, the corridor through which Russian ships and submarines enter the North Atlantic.