Cork or Killarney

Given what you say you want to do ( Dingle and Ring of Kerry) then Killarney makes more sense. But, Killarney is a long way from Dublin and you will waste a lot of your limited time getting there, and then getting back again to fly home. I have not checked the schedules recently, but it took me four and a half hours by train to go from Dublin to Killarney, so even if you catch a train at 7am it will be almost lunch time by the time you get there. Have you checked to see if there are any half day tours you might be able to do? With three nights you only have two full days, and you still have to get back to Dublin to fly home so you may not have time to do two full day trips if you have to use another one of your days to get back to Dublin. If it were me, I would go to Galway instead as it takes half the time to get there, and there is a bus service to the airport. You need to spend some time with the train schedule and the schedules, and availability, of tours to see what will work, and whether it’s worth it to go all that distance to possibly only do one day trip.

I would do either the Dingle tour or the Ring or Kerry tour, not both.

Dublin to Killarney is 3 hours 15 minutes on the direct train. If I went to Cork instead it would be 2 hours 32 minutes by train. Cork to Killarney is 1 hour 20 minutes by train.

I had looked into Galway but the sights in Cork and Kerry interested me more plus I was thinking I would include Galway as part of my next trip when I cover Northern Ireland, Donegal, Sligo and Connemara.

How about the 3-day Rabbie’s Dingle, Killarney & Wild Atlantic Way tour:

https://www.rabbies.com/en/ireland-tours/from-dublin/3-day-tours/dingle-killarney-wild-atlantic-way-3-day-tour

You’ll see a lot more in those 3 days than you would on your own.

Carrie- I will check into the tour. It has availability the week I will be in Ireland, but the pricing given for B&Bs / hotels isn’t exact so I’ll inquire since I’m booking last minute. I do like that the tour would stop at the Rock of Cashel as well, as my great-great grandmother was from Tipperary and I’m a little sad I won’t be making it there on this trip.

If you end up taking that Rabbie’s tour, I’d love to hear about it. I’m considering a few of the Rabbie’s tours for next year.

Good luck deciding and have a great trip!

It’s a tossup. You just have to choose your priorities.

But if you do end up in Cork and really want to see the Rock of Cashel, there’s a regular bus that goes to and from (245X, I think). 12:00 departure, 4:11 return, and takes about 1.5 hrs each way.

You can fly from DUB to Kerry Airport in 55min, then take a bus to Dingle in about 2 more hours. Or Killarney instead in about 1.5 hrs. You'd have to check the connection times if it sounded like an alternative.
I've considered the flight several times but have always opted to keep our rental car and drive back to DUB.

Cork itself is pretty meh IMO, but it provides a good hub to Cobh and Kinsale, both of which are charming. Cobh doesn't demand a full day, though. And I don't believe one can travel to Kinsale by train.

Can't help you with Killarney and the Ring of Kerry or Dingle, unfortunately. That's for my next trip to Ireland.

The bus to the Rock of Cashel, the 245X, is a Dublin to Cork bus.
Buses leave Dublin at 0800 (2:11 journey), 1200, 1400 and 1800; and Cork at the same times. So that opens up other possibilities.
They are double deck coach buses.
There is also bus 332 every 3 hours from Limerick to Cashel- journey time 1:49-
run with single deck coach buses so various possibilities.
You could also do Cobh on the half hourly train in a morning, then transfer to Kinsale by bus which starts hourly at Cobh Railway Station, then calling at the bus station.