Aktio–Preveza Undersea Tunnel, Tunnel in Greece

The Aktio-Preveza Undersea Tunnel is an underground passage beneath the Ambracian Gulf in Greece, connecting Epirus with the city of Preveza to the north and extending toward Aetolia-Acarnania. Measuring approximately 1,570 meters in length with over 900 meters submerged, it features two driving lanes and a pedestrian walkway.

Planned in the 1990s and completed in 2002, this passage replaced the long and weather-dependent ferry journey across the gulf with a direct route. International teams from Denmark and Greece collaborated to construct it, addressing the seismic challenges of this earthquake-prone area.

The tunnel takes its name from Aktio (Actium) and Preveza, the two shores it links at the mouth of the Ambracian Gulf. Its opening on 28 June 2002 was performed by Prime Minister Kostas Simitis, and the crossing replaced a ferry route that had served the strait since antiquity. The 1897 lighthouse and gun emplacement on Cape Akri stand beside the Preveza approach.

The tunnel carries a single two-way carriageway with a 4.0 m side lane and a 1.3 m pedestrian sidewalk in each direction, so walkers can cross on foot. Toll is 3 euros as of January 2026. Clearance inside is 5.4 m high and 10.6 m wide.

It is Greece's only underwater tunnel and a rare engineering achievement in an earthquake-prone area. The structure was fitted with special supports to handle ground movement during seismic activity, making it a notable example of engineering adapted to local geological conditions.