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.