Many of the areas are quite spread out and there aren't any particularly high density regions.
A large national park a short drive south of Dublin there is plenty of scope for bouldering. The main area lies in the jumble of boulders that are underneath Glendalough.
The Burren Edit
Plenty of scope for bouldering on the limestone edges around here.
Eire has a maritime climate, which means that just like the UK, it can be very wet, if not wetter a lot of the time.
Dave Flannagan has done an excellent job of documenting the bouldering in Ireland on his web-site The Short Span and in 2011 published the countries first guidebook which was updated to a second edition to include new problems recorded since the first edition.