The cause of the C-Lion1 underwater cable break in the Baltic Sea is under investigation. It is the only undersea cable linking Finland to central Europe.

Authorities in Finland are currently investigating the cause of a break in an underwater cable located in the Baltic Sea. This cable, known as C-Lion1, runs from southwest Finland to Germany.

On Monday, Cinia, the state-owned data service provider responsible for the cable, reported that a fault had been detected in the C-Lion1 cable. As a result of this fault, communication connections relying on the cable have been disrupted. The company has confirmed that investigations are ongoing to determine the cause of the disruption.

Samuli Bergström, communications chief at Finland’s National Cyber Security Center, Traficom, also confirmed the break. In comments made to the Finnish Broadcasting Corporation YLE, Bergström explained that while disturbances like this are not uncommon, they can have multiple causes, such as weather conditions or damage caused by shipping activity. He emphasized that the priority is to identify the issue and take corrective measures.

Bergström also reassured the public that Finland’s data connections are supported by several routes. The break in the C-Lion1 cable, while significant, is not expected to have a noticeable impact on the average citizen, though it may place additional strain on other existing communication channels.

The C-Lion1 cable spans nearly 1,200 kilometers (approximately 750 miles) from the German port city of Rostock to Finland’s capital, Helsinki. Commissioned in 2016, it is the only undersea communications cable connecting Finland to Central Europe, according to Cinia.

This incident comes amid a backdrop of heightened concerns over the security of undersea infrastructure in the region. In October 2023, the Balticconnector gas pipeline between Finland and Estonia was also damaged in what Finnish authorities suspect may have been a deliberate act. Additionally, a similar undersea cable between Sweden and Estonia was damaged around the same time.

Both Finland and Sweden joined NATO after Russia's invasion of Ukraine in February 2022, ending their long-standing neutrality policies.