A bridge across the Irish Sea is a ridiculous idea, but the ferries between Northern Ireland and Scotland are the most expensive in the UK – Slugger O'Toole
Brexit could mean chaos for Irish trade, too | The Economist
Routes en kortingen van Irish Ferries | Interrail.eu
Irish Ferries - Wikipedia
Ferries to Northern Ireland | UK & Europe Routes
Ferry to Ireland - FerryGoGo.com
First ferry route from Ireland to Spain | FCM Travel