Irish Ferries travel from Wales to Dublin (from Holyhead on Anglesey) and Rosslare (from Pembroke), with regular ‘Kids Sail Free’ offers. Dingle town is about a 4-hour 30-minute drive from both Dublin and Rosslare.
There are flights to Kerry Airport in Faranfore from London Stansted and Luton with Ryanair for a very limited time in summer. Otherwise, flights from various UK airports serve Cork, a 2-hour 20-minute drive from Dingle town.
A hire-car is essential for exploring County Kerry with kids if you don’t bring your own vehicle.