Return rental outside Dublin

Why the reluctance to return the car at the airport? It's pretty straightforward to do so and it would only be a 25 minute taxi ride from there to the front door of your accommodation.
There are some rental car concessions located along South Circular Road which might work if you're arriving from the south or west of the city, and which wouldn't require you to venture into the rabbit warren of central Dublin with the car. Can search on google maps to see what pops up. Their operating hours will be much more restrictive than the offices at the airport, so you'll need to crank that into your planning.
You could check the route map for Irish Rail to see if there's an easy way to drop the car at or near your last stop (Cork, Killarney, etc) and then train back into the city.
As I recall there are also several rental car concessions located in Dun Laoghaire (the ferry port south of Dublin), from which you could catch the DART back into the city.

Edited to add: the airport return location is on Swords Road about a half mile from the terminal, so you don't have to go anywhere near all of that congestion if that's your concern. All in all, returning at the airport will be the least convoluted way of doing it (IMHO).

The airport makes a great deal of sense…….

Thanks for your feedback. We will be in Kilkenny so I thought it might make sense to return somewhere outside Dublin since we are coming from southwest of the city. I didn’t think about the restriction on operating hours at the smaller rental spots so will definitely check that. I appreciate the feedback.

I’m now wondering to, whether it makes sense to start in Galway or perhaps a different town in the west that would be east access to all the places we want to see on the West coast. Is Galway worth a visit for a day?

Jodi

Galway is very popular with many on this forum. I didn't like it all that much, but I could agree it is worth a day. To me, it's main purpose is a good launching point for trips to places that are far more interesting to me such as the Aran Islands. I think even a day trip to Aran Islands would be quite popular with your sons. You can rent bikes (I went for the electric bike!) and tour the island as a family.

Another nearby attraction that I think would be quite popular with your sons is the Ireland School of Falconry at Ashford Castle where you can go on a "Hawk Walk". Participants get to fly hawks as they walk through the forest and grounds of the Castle. It was my sister's highlight of the entire trip.

I think you will have to use a third-party consolidator to rent in Galway and return outside of Dublin. Although there are a number of Hertz franchises on the South Circular Road in Dublin (which would be easily accessed when coming from Kilkenny), the problem is that they are individually owned franchises that may or may not have a relationship with an agency in Galway. I tried making a dummy reservation using Auto Europe (never used them but a lot of folks here like them), but came up with "sorry, can't help you". Then I tried Kayak and found a number of choices. Give it a try and see what happens. You'l need to call up a map app to see exactly the agency's location. Having said all that, it might just be easier and cheaper to return to the airport.

Taking the express bus to Galway upon arrival in Dublin and spending the night there is a still good plan I think. There's a lot to be said for getting a good night's sleep before getting behind the wheel, and being pre-positioned in Galway the next morning would allow you to get a running start as you begin your driving itinerary, whether you choose to spend any time in the city or not ... and I would agree with the "not" since it isn't one of our favorites either. Good base to start from though.
Both Budget and Europcar have concessions in Galway, and I'm pretty sure that they permit one-way rentals with a return back in Dublin ... with locations at the airport and in the city. Check their respective websites to verify that.
Suggest spending the extra money for a vehicle with automatic transmission. Will make for a much more pleasant driving adventure than a manual, which will be the default selection when you book.

Many thanks to all for sharing your thoughts and advice. This will be our first trip to Ireland. We are excited but a bit overwhelmed with the decision of what to see and what to save for next time.

Yes, take the bus to Galway. When you're ready, pick up your rental car there (there are plenty of car rental options). Where to return it? Return it at/near where you are when you are done with it in the west/southwest of Ireland...just find some place that meets both of the following criteria:

• Has a car rental agency nearby (and one that's open on the day you want to drop it off -- IME some car rental agency offices are closed on Sundays, which may limit your options)
• Also has (or is near to) rail station

Ireland's rail system isn't as extensive as many European countries, but it does extend to much of the country. No TVG or other high-speed lines, but perfectly modern, comfortable, and a much better way to get across Ireland and back to Dublin than driving. Here's a link to the rail system map: https://www.irishrail.ie/en-ie/travel-information/station-and-route-maps/ireland-rail-map

On our last tip there, after arriving in Dublin, we walked off the plane, got on the express bus to Galway. A few days later (after a visit out to the Aran Islands and back to Galway) we picked up our pre-booked car, and drove it all around the west/southwest. When we were done, we returned the car at Cork (airport), got on the train (in Cork town) and rode that back to Dublin. Easy, relaxing, perfect for us.

Biggest challenge was finding a location with both an agency (and one that would be open on a Sunday morning) and a rail station within a short taxi ride away. Our car rental agency helped figure that out (I gave them a list of rail stations that were within striking distance -- we ended our time in the southwest in Kinsale, and there would have been closer places we could have dropped the car -- eg Killarney -- but those were closed on Sunday mornings...).

Thanks for your input, David. We are hoping to attend the Irish Open (south of Kilkenny at Mount Juliet). Our teens are golfers and this aligns well with our trip dates. Given all the advice, I'm now thinking we could possibly return our car in Kilkenny and train back to Dublin.