12 days in Ireland using public teansportation

We're doing something similar, but a bit in reverse of your trip. We're flying into Dublin then taking a bus to Cork & then another bus to Kinsale. After a few nights in Kinsale we're traveling to Dingle via private car/tour. We're spending a few days in Dingle then making our way up to Galway via private car/tour. Galway will be our home base for a few days and then we're taking a train to Dublin & then up to Belfast. After a few days in Belfast we'll take the train back to Dublin and spend the remainder of our vacation there until we fly out. We decided NOT to rent a car because we want to enjoy the trip & know the stress of driving on the opposite side of the street on curvy country roads would be hell! Hiring a few private car rides is a bit expensive, but the rides are also tours. Went we wanted to get directly somewhere we're taking a bus or train.

How are you planning to get from Belfast to Galway? I'm assuming you aren't going via Dublin as you are ending up there? If not, I'd suggest Sligo as a possible stop between Belfast and Galway (you can get there by bus via Enniskillen OR via Londonderry/Derry. Either way you are talking about nearly five hours journey).

Then do Sligo to Galway which is about 2.5 hours on the bus.

If you want a base stop between Galway and Cork, I would suggest Killarney - 4-5 hours on the bus via Limerick.

Killarney to Cork is about two hours on the bus.

If you want another stop between Cork and Dublin, Then Kilkenny would work.

All of these are popular tourist basis with good public transport links between them and don't require a major deviation from you planned route.

Remember that Northern Ireland is part of the UK so the public transport provider is different from Ireland www.translink.co.uk

The four main ones I used were Dublin, Killarney, Galway and Belfast. I purchased a bus/train pass that could be used 8 days in two weeks so since I had a three week trip planned I started with four days in Dublin, then did all my travelling from place to place, and ended with four days in Belfast. This worked well, but did require a lot of planning. If you search this site for this topic you will get quite a few results as this question has been ask many times with some good responses.

Echoing the travel by public transportation route and maybe to encourage you, we are flying in and out of Dublin, and spending 26 days in Ireland/Northern Ireland/Southern Scotland. We are using a combination of bus, train, and ferry (including one from Belfast to Scotland), to see Cliffs of Mohr/Burren, Donegal, Derry, Ballycastle, Edinburgh, St Andrews, Dundee and the islands of Rathlin, Inishmoor, and Isle of May. We have 12 days of walking tours (Burren Way and Fife Coast) and a couple of days with bike rentals. We take a short flight from Edinburgh back to Dublin. Besides our one day stays, we are basing with multiple days in Doolin, Belfast, St Andrews, and Dublin. It's a little crazy but It can be done without a car. :-)