I'm convinced - I'll take the train from Belfast to Dublin! Do I buy the ticket before I leave or wait until I get to Belfast? Thanks for your help!
I'm not sure about this specific journey, or travel in Ireland either (sorry), but for my upcoming travels in France, I booked one train ticket here, and we're waiting on the other until we get there. Here's why: the one we booked was a "prems" rate, so it was an advanced-purchase special price. The other was just the regular fare (and I've heard it should be cheaper at the train station). Also, the one we booked required reservations, and the other doesn't. For us, it was a question of comfort: Since we want to be on THAT train, was it worth it to buy it now? And likewise, even though we wanted to be on a specific train for our second journey, buying a ticket couldn't guarantee that since there aren't reservations for it. As far as your route, I'm not sure, but I hope my experience helps! Good luck!