I am leaving my travelling group early to return home and need to find transportation from Killarney to the Shannon Airport. I have read that the trains are not reliable especially on Sundays. Any suggestions would be greatly appreciated.

You could get a bus - you will need to change at Limerick bus station, from where it is about 25 mins to shannon airport.

Timetables are available at www.buseireann.ie. Just make sure not to tick the box "direct journey only" and it will give you all the options. Looks like it takes about 3 hours all in to get from Killarney to Shannon Airport.

Getting the train would probably take longer - if you get a train you will probably need to change trains at least once before arriving at Limerick and from Limerick take a bus / taxi to Shannon. If the times suit, it's probably easiest just to get the bus. Train timetables are available at www.irishrail.ie.

Irish trains are, in my experience, quite reliable. The problem with Irish trains is that the network is limited so many journeys are only possible by bus. Irish buses suffer from traffic congestion around the towns. Irish economic growth has led to a big increase in traffic which now causes traffic jams. The buses are reliable but can no longer be punctual so you should allow extra time in case of delays.

Thanks for the information. I'll check with the bus and have already checked on train service.

If you don't mind driving, you could pick up a car at the Kerry airport, then drop off at Shannon, possibly at a good rate. Another option, would be to seek out a private bus service that goes to either Limerick or Shannon. The bus service works, but at a slow pace and the train will have to circumnavigate the south before finding Limerick, plus it is expensive. Have a great trip