The Republic of Ireland’s third underwater motorway opened on 27 July 2010 in Limerick City.

The €605m ($781m) Limerick tunnel is 9.8km long and is part of the M7 Limerick Southern Ring Road phase 2 project.

The new road links the M7 Dublin to Limerick route with the N18/M18 Galway to Limerick road and completes the southern bypass of Limerick City.

About 27,000 vehicles are expected to use the tunnel and its associated dual carriageway every day, reducing traffic volumes along three existing bridges in Limerick City by one third.

The Limerick tunnel is the first to comply with legislation under the new European Tunnel Safety Directive, according to the Irish Times.