Finland’s border guard tests underwater cable threat detection system in Baltic Sea

Finland’s Border Guard has conducted trials in the Baltic Sea of a new acoustic monitoring system designed to detect threats to subsea cables, state broadcaster Yle reports.

The technology uses distributed acoustic sensing, where fibre-optic cables track and measure unusual vibrations on the seabed. The method aims to identify risks to critical underwater infrastructure, including data and power cables.

The tests follow a series of cable incidents in the Gulf of Finland. Last New Year’s Eve, an anchor from the cargo vessel *Fitburg*—detained by Finnish authorities—was suspected of damaging an Elisa subsea cable linking Helsinki and Tallinn.