Communication cable: Submarine cable damaged in the Baltic Sea

Damage to communication cables between the new NATO members Finland and Sweden and their allies Germany and Lithuania has been reported in the Baltic Sea. The Finnish state-owned company Cinia announced that a defect had been discovered in the C-Lion1 undersea data cable between Finland and Germany and that communication links via the cable had been interrupted as a result. The cause of the error is still unclear and investigations are ongoing. The Finnish Foreign Ministry and the Foreign Office in Berlin are “deeply concerned.”

In the evening, the Lithuanian broadcaster LRT reported, citing the Swedish communications company Telia, that a cable between Sweden and Lithuania had already been damaged on Sunday.

Swedish authorities are investigating both incidents

In response to a dpa request, a Telia spokesman confirmed that the Arelion communication cable between the Swedish island of Gotland and Lithuania had been physically damaged, but that Lithuanian Telia customers had not experienced any major disruptions as a result.

However, it is hoped that the marine fiber optic connection will be restored soon. In Sweden, Civil Protection Minister Carl-Oskar Bohlin told broadcaster SVT that Swedish authorities were investigating the two incidents.

The only undersea data cable directly from Finland to Central Europe

C-Lion1 runs 1,173 kilometers from the Finnish capital Helsinki to Rostock in Mecklenburg-Western Pomerania, partly along the same route as the Nord Stream pipelines that were destroyed two years ago. The cable went into operation in spring 2016 and is the only undersea data cable that runs directly from Finland to Central Europe.

Finnish media described it as important for Finnish consumers’ internet connections, but the Nordic country is also connected to the rest of Europe through numerous other routes. Finnish online users are said to have not felt any effects so far.

When it went into operation in 2016, it was said, among other things, that the new digital highway offered the shortest and fastest connection between Central Europe and the most important data center locations in Northern Europe.

Cinia assumes that the cable broke at the bottom of the Baltic Sea and was severed by external influences, such as an anchor or a bottom trawl. A company press conference said the incident occurred in Swedish waters outside the busiest shipping areas. There is currently no information about intentional sabotage.

Foreign ministers worried

In a joint statement, Federal Foreign Minister Annalena Baerbock and her Finnish counterpart Elina Valtonen said: “The fact that such an incident immediately raises suspicions of intentional damage speaks volumes about the volatility of our times.” A thorough investigation is underway.

“Our European security is threatened not only by Russia’s war of aggression against Ukraine, but also by the hybrid warfare of malicious actors,” the statement continued. “Protecting our shared critical infrastructure is critical to our security and the resilience of our societies.”

Duration of repair open

How long it will take to fix the problem on C-Lion1 is still unclear. According to Cinia, subsea cable repairs typically take between 5 and 15 days. To do this, the cable must be lifted out of the sea onto a repair ship that will come to the affected area from Calais, France.

Critical infrastructure is in the public eye, especially in the Baltic Sea

Since the Russian invasion of Ukraine in February 2022 and the explosions caused by sabotage on the Nord Stream pipelines in the Baltic Sea the following September, the situation of critical infrastructure, especially in the Baltic Sea, has become the focus of the public and especially NATO.

Under the impression of Russia’s actions in Ukraine, Finland and Sweden decided to join the defense alliance – Finland had already been accepted into the alliance as the 31st member in April 2023, and Sweden followed in March 2024 as NATO member number 32.

Almost a year ago, the Balticconnector pipeline between Finland and the other NATO state Estonia was damaged – according to Finnish investigators, most likely by the anchor of a Chinese container ship called the “Newnew Polar Bear”. It is still unclear whether the incident was an accident or deliberate sabotage. A data cable between the two EU countries was also damaged in the process.