You could definitely take a ferry from England to Ireland.  Depending on how much time you have, you could fly to London, spend a few days there seeing the sights, take the train to Swindon and stay in that area a few days.  You could rent a car and see that area (there are also tour companies that will take you privately where you want to go), then take a train from Swindon to Liverpool (for instance) and there's a ferry across to Ireland. Fly back to the States from Ireland. I'm not saying this would be a cheap trip, but if it's the trip of a lifetime, it's definitely possible to visit both countries.  See a travel agent who specializes in the U.K. if you have one in your area.  Getting a Brit-rail pass is a good idea and I think it covers Ireland, but check to be sure.