When travelling on such short distances, you can take into account also busses and carpooling options: with some luck you will find very cheap options, even if you book on short notice.
What are the departure and arrival stations in Clondalkin and Dublin?
The trains to Dublin will leave from Clondalkin Fonthill and will arrive at Tara Street, Dublin Heuston, Dublin Pearse or Dublin Connolly.
How long does it take from Clondalkin to Dublin and when do the trains leave?
The first train to Dublin leaves at 07:09, whereas the last one at 20:09. On average, the journey lasts 33 minutes, but with the fastest connections you will be in Dublin in 16 minutes.