Travel from Ennis to Dublin Airport

I am in Ireland in October 2024 and will be finishing a tour in Ennis and need to get to Dublin Airport to fly out.  I'm keen on a train trip but bus trip will be fine as well. 
It looks like I should look at the Limerick train line which services the Ennis area, but its not very clear to me.
What are my best options for that trip. 
I know the train trip is around 3.5 hrs and the Bus trip around 4 hrs, which fits in with my itinerary.
Mick

Hi Mick,

How nice that you'll be with us next autumn! 

According to the Rome 2 Rio website, you have multiple train options to get to Dublin Heuston (you'll still need a short shuttle bus ride to the airport after that). I would recommend switching in Limerick (Colbert) instead of Athenry, as the transfer times seem more comfortable. Now of course it depends on the time of the day and both options are quite similar. You can get tickets ahead of times through the Irish Rail website.

I'm eager to hear what you've got planned during your tour! 

Cheers,
Antoine