Firstly, the best thing to do is check with your service provider at home to make sure your phone is compatible with G.S.M. (Global System for Mobile), used in Europe. Ask them if they have an international plan, some may even have a “use it like you do at home” plan.
Or you can get your phone unlocked and buy a SIM card when you get here, put minimal credit on the card, eg €10 to get data and calls. Use WIFI whenever you can to save this credit. If you are a regular traveler to Ireland, you could consider buying a cheap phone here to use on your travels.
If you need to make local calls, for example contact your accommodation or book a restaurant table for your evening, while on an Experiencing Ireland tour, your guide can facilitate this.
