Norbay operates the Dublin - Liverpool service for P&O Ferries alongside sister vessel Norbank and the European Endeavour.  Built for North Sea Ferries the vessel operated the Hull - Rotterdam route. In 2002 Norbay along with sister vessel Norbank transfered to P&O Irish Sea and took up service on the Dublin - Liverpool route operating back to back. In recent years the Norbay has provided refit cover for P&O's Larne - Cairnryan vessels, the vessel also completed berthing trials at Troon in 2011. To date it is the largest vessel ever to have visited Troon.