Dublin Airport (The East)
This is the largest airport in the Republic of Ireland. It is served by an ever growing road network which will makes it easy to get to. In the Summer it can be crowded which some people may not like but having traveled all over Europe, it's not too unpleasant. It's a small airport in International terms. Longer term, a new Terminal is planned to be added and a direct rail link to Dublin city center. Unlike most European cities there is no rail link to the city center but one is in the planning and will be constructed. Look to Taxis (which can be expensive) or the Bus service which is more affordable. As ever, there is adequate car hire. It takes less than an hour to get to Dublin city center.
Belfast Airport (The North)
Belfast International Airport is located centrally within Northern Ireland and is also convenient to the border regions of the Republic of Ireland. Belfast city centre is just 20 minutes away by car, whilst the historical city of Londonderry in the North West is approx 1hr 25 minutes away by car.
Car hire is advisable for visitors who wish to travel around Northern Ireland, and there are five car hire desks located in the arrivals hall, all of which are open for all inbound flights.
Shannon Airport (South-West)
If you prefer to travel to the South-West of Ireland, this is the place to fly into. The airport industry in Ireland has recently changed and each Airport are becoming independent business units and therefore there may be better deals on offer than previous. Shannon has historically been part of a 'stop over' agreement with the US to ensure traffic to the airport. The compulsory stop over by flights from Ireland travelling to the United States is to end in 2008 as part of the new Open Skies agreement between the US and the EU.
Cork Airport (The South)
Cork is the second capital of Ireland and is a good place to visit. Many fly into Dublin instead of Cork because there are more direct flights to Dublin and it's becoming easier by road to travel to Cork because of the increasing number of small-town by-passes. If you're thinking to flying to Cork, Ryan Air operates cheap flights but more local Irish prefer to drive. The choice is yours!
Knock Airport (The West)
This is one of the smaller airports and is based in Charlestown. It's closer to the extreme Western Seaboard. It forms part of a strategic hub for the West as outlined by the government.