Stena are having a flash sale on Foot Passenger Fares of £15 Single on the following routes for travel until 18 December.
The sale is on until 2259 BST on 1 April.
Cairnryan to Belfast, Holyhead to Dublin, Fishguard to Rosslare (These 3 routes on all sailings).
and
Liverpool to Belfast and Harwich to Hook of Holland (These routes on day sailings only)
In all cases these fares apply to both directions of travel, and are non refundable and non amendable.
EDIT- The Sale is now extended to 8 April