Dublin Airport is an international hub and you will be able to fly directly to it from most European and US cities. On arrival you will be able to catch a bus in front of the airport to the city centre (journey time is 25 minutes by car/ bus or more if the traffic is bad). You will also find taxis available at both terminals. Taxis are exempt from laws on car seats so if you are not bringing your own it would be safer to book a taxi in advance in order to ensure availability (See ‘Ireland, General Information’ for further details).
Many hotels also arrange shuttle buses to and from the airport so check with your hotel in advance. Car rental agencies are located in both terminals and remember that in Ireland you drive on the left. If you do decide to rent a car, make sure to book your car seat in advance.