Ireland has ferry links from Wales, Scotland and England — the right one depends on where you start and where in Ireland you're heading.
From Wales (for Dublin and the south)
Dublin → Holyhead is the workhorse: about 3¼ hours, up to eight sailings a day with Irish Ferries and Stena Line, and the natural choice from the M6/North Wales corridor. From south Wales, Rosslare → Pembroke (about 4 hours, Irish Ferries) and Rosslare → Fishguard (about 3½ hours, Stena Line) land you in Ireland's south-east — better for Waterford, Kilkenny and Cork.
From Scotland (for the north)
The North Channel is the quickest sea crossing to the island: Belfast → Cairnryan (about 2¼ hours, Stena Line) and Larne → Cairnryan (about 2 hours, P&O) both run frequently year-round.
From England (sail overnight)
From the north-west, Dublin → Liverpool and Belfast → Liverpool take about eight hours, with overnight sailings that swap motorway miles for a cabin and breakfast on arrival.
Choosing quickly
- Fastest to Dublin: Holyhead.
- South of Ireland with a car: Pembroke or Fishguard to Rosslare.
- Northern Ireland / Scotland: Cairnryan crossings.
- Skip the drive across Britain: the Liverpool overnights.
All these are car ferries; check in typically closes 30–60 minutes before departure, and you'll want photo ID for the crossing.