C-Lion1 - Cable Break

In the early hours of 18 November 2024, the C-Lion1 submarine telecommunications cable, which runs roughly 1,173 kilometres between Helsinki (Santahamina) in Finland and Rostock in Germany, was severed in the Baltic Sea. Cable operator Cinia reported the fault occurred after 0200 UTC, in the Swedish exclusive economic zone east of the southern tip of Oland, and that it was the first break since the cable entered service in 2016. The cut came less than a day after a separate cable, the BCS East-West Interlink between Sweden and Lithuania, was damaged on 17 November in the same general region.

Network-measurement analysis by RIPE Labs found that traffic largely rerouted around both faults, with only modest latency increases and no visible packet loss. Cinia repaired the cable by 28 November 2024 and said disruption to Finnish society was minimal thanks to alternative routes. Suspicion centred on the Chinese-flagged bulk carrier Yi Peng 3, which had departed a Russian port and whose tracked course passed near both damaged cables around the times they failed. Investigators examined the theory that the ship had dragged its anchor across the seabed, though the cause and any intent were not conclusively established.

German and Finnish authorities treated the near-simultaneous damage to two cables as a likely deliberate act, with their foreign ministries citing concern over hybrid warfare amid heightened tensions with Russia. Attention focused on the Yi Peng 3, a vessel that had sailed from a Russian port, raising questions about possible links to Russia and the broader shadow-fleet context, though officials noted accidental anchor damage remains common in the region. As of the available reporting, attribution to any party, and whether any damage was intentional, remained unproven and under investigation.