Hi! I recently visited Irelnd and went nude at a beach. Our tour guide said its not officaily a nude beach but there were prob 30 naked people there. I dont remember the name it was on the west coast just south of the cliffs of Moher. I think it was north of Killarny. Hope that helped. Sorry not better exact location.
There are some clubs in Ulster (two in your area I think) but no nude beaches. For the latter you will have to cross the border. There are two good beach venues near Dublin, one to the north of the city and one south near Arklow, at Brittas.
To find out about the clubs in Ulster you should join British Naturism and contact your regional organiser.