Another damage to the undersea C-Lion1 cable on the Baltic Sea

On 21 February, the Swedish authorities confirmed the initiation of an investigation into newly discovered damage to the Baltic offshore telecommunications cable. The incident concerns the C-Lion1 cable that connects Finland to Germany and runs through the Swedish economic zone near Gotland. That's the third damage to the same cable in the last three months.

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The investigation is conducted by the Swedish prosecutor and the armed forces of the country. The Swedish Coast Guard unit was assigned to the siteKBV 003To investigate the damage.

New investigation and international response

Swedish police reported that they were investigating the case as part of a preliminary investigation into suspected sabotage.The purpose of the proceedings is to establish, whether the cable was damaged by deliberate action and whether the failure occurred recently, or whether it is an older damage that was only detected now.

Swedish Prime Minister Ulf Kristersson confirmed a few days earlier that the authorities were treating the incident with the highest seriousness. "We treat all cases of critical infrastructure damage in the Baltic with the highest seriousness, especially in the context of current security threats," he wrote on platform X.

Finnish company Cinia Oy, a cable operator, reported that the damage did not affect the functionality of telecommunications connections. It is stated that the data transmission is carried out without interruption. Nevertheless, the company has reported the case to the Finnish National Bureau of Investigation (NBI) and is demanding a thorough analysis of the event.

Damage series and possible causes

The undersea C-Lion1 cable has been damaged before. On November 18, 2024, the first break-up was detected, which the investigation showed was the result of external interference. After the repair, completed on 29 November, the cable again stopped operating on 25 December.This timeThe likely cause was damage caused by the tankerEagle Sin the Gulf of Finland. The accident was successfully removed on 6 January, but Finnish company Cinia Oy demands that the unit be occupiedEagle Sto secure their compensation claims.

The current investigation focuses on new damage, but so far no detailed information on its scale and cause.

The European Union strengthens the protection of critical infrastructure

The incident coincided with the announcement by the European Commission of new measures to protect offshore infrastructure. Kaja Kallas, vice-president of the EC and High Representative for Foreign Affairs and Security Policy, announced a number of measures to better detect threats, to repair damage more quickly and to deter potential perpetrators.

"No area of life is free today from threats or hostile actions," emphasised Kallas. "We need to use all our capabilities – both military and civil – to monitor the situation in the Baltic more effectively, assign responsibility for incidents and impose sanctions on the perpetrators of sabotage."

The Common Position presented after the Helsinki meeting provides for the implementation of new initiatives from 2025 to 2026. Key assumptions include:

strengthening the monitoring of offshore infrastructure,
development of new cables with increased resistance to damage,
financing of technologies for the reduction of connections,
coordinated risk assessment for existing and those to be arranged,
priority list of infrastructure projects of European importance.

The plan also envisages tightening sanctions against those responsible for sabotage and intensifying action against the so-called ‘sabotage’.Shadow fleet– individuals used to circumvent international restrictions.

According to safety experts, further damage to C-Lion1 may indicate an increasing threat to the offshore telecommunications infrastructure in the Baltic Sea region.More and more incidentswith damage to offshore cables in recent months have raised concerns that they may be part of hybrid activities that the Russian Federation may be behind.

What the media say about the damage to the cableC-Lion1?

Several articles have already appeared online, mainly in Scandinavian media. Swedish SVT Nyheter and Dagens Nyheter emphasise that the investigation is conducted in close cooperation with the military and other international partners. Finnish Yle points out growing concerns about the security of critical infrastructure in the Baltic, especially after last year's incidents.

It is worth noting that the issue of damage to offshore cables is increasingly emerging in the context of possible hybrid actions, both in the analyses of security experts and in official government communications.

Written by Mariusz Dasiewicz