Hi Kathrin,
The Aran Islands are fantastic to
explore by bike. :) There are no cars allowed on the ferries to the islands, so it is the perfect place for a peaceful bike ride. The routes are suited for cycling, with gentle roads and relatively flat circuits, and you can rent bikes there if necessary. I recommend taking your time to explore the island, and if you have time to spare try to catch a ferry to one of the other islands.
Coral Beach is located in Carraroe, County Galway. It is on the island of Ireland itself, so you can drive straight to it. :)
Let us know if there is anything else you need, and I wish you a great weekend!
Melin