Our son was interested in fishing several years ago when he was 12 and we were off to Ireland for a wedding, so we did some fishing, but nothing big time.
We did this day trip from Courtmacsherry, a bit southeast of the city of Cork: http://www.courtmacsherryangling.ie It was a good day trip and there were some serious fishing tourists on that trip from several European countries.
In Clifden on the west coast, we let our hostess know ahead of time we wanted to arrange a fishing trip, and she made arrangements for a lovely evening trip on a small boat, where the captain served teas and cookies, and played his fiddle!
We were then in Ballina at a wedding, and the hotel had fishing tackle for hire to fish in the local river. Getting our son set up meant he had to get a license which was not a big deal, until about 6 months later he got a ticket in the mail from the Fishing Board because he hadn't turned the license back in! (My husband sent a letter off and all was fine.)
I would check out the link above for leads, and also look at the 'requirements' link. That seems confusing, but I think the take-away from it would be to know that you should at least ask if a license is necessary when you make plans for a particular trip.