I need help with an Ireland Itinerary in Sept that will fit around a half marathon

First, making certain you understand that neithet RS or his staff answer inquiries on this forum. Instead fellow travelers make suggestions and try to be helpful.

With that in mind, I’ve driven the entire island twice. Most recently 4 years ago when I drove from Belfast in Northern Ireland to Dingle and from
Dingle back to Dublin. Single female, born when Eisenhower took office.

From my point of view having a car in Eire is a necessity. Makes it so much easier to see Ireland’s beauty and explore the back roads. The latter is my travel style.

Given your travel I would suggest flying into Shannon and Departing from Dublin on a return flight to the States.

Doolin is about an 1.5 hour drive from Shannon. Spend a night or 2 there as it is an easy drive to the Cliffs of Mohr.. There are also trails you could follow to stretch out legs. From Doolin you could drive to Gallway if you wanted more of city atmosphere.

Personally I loved Dingle as I drove over the Gap of Dunloe to Killarney National Park. It was a November visit and all the Fall colors were gorgeous.

I’d look at the 1/2 marathon route and see if there’s a nearby Premiere Inn. This hotel chain is popular and well run. In the UK I’ve stayed at a few. Clean, safe, and well priced. I’d also book now. One less thing to be concerned about.

Since you haven't bought your tickets yet try to arrange your travel so that the half marathon is at the beginning or end of the trip. That will minimize backtracking. Also bear in mind that you pre-clear US immigration in Ireland. So you need to be at the airport checking in for your return flight 3 hours ahead of departure. Since the Cliffs are in the west and Dublin is in the east the suggestion to fly into Shannon in the west and out of Dublin in the east, or vice versa, is a good one. From many of the major cities in the west (Galway, Cork, Limerick, Killarney) you can take an organized day tour to the Cliffs. And from those major cities you can take a bus or train back to Dublin (or vice versa). When you say your mom wants to see a castle does she mean a defensive castle or a manor house? Defensive castles will not have beautiful tapestries, silver services or mannequins dressed in period clothes. But they will describe and explain how a defensive castle was used.

These are great ideas. I think flying into Shannon and out of Dublin is a great idea! I will do some research on cities you mentioned, I really don’t want to have to unpack and pack everyday.

I wasn’t clear on whether the 7 nights includes the marathon time or was in addition to it.

First I do second car rental.

I assume you will need a minimum of 2 nights in Dublin: 1 before the marathon and 1 after it and before you fly home. But 3 nights would be better.

If you then have 4 nights remaining, your question becomes whether you want to divide that into 2 stops or keep it at 4.

Options for the Cliffs would be Doolin, Ennis, Galway for starter ideas. Galway would position you for one day to the Cliffs of Moher and one day to drive through Connemara. That would be 3 nights. You could easily add another night to Dublin if you don’t want to move around as many times.

If you don’t mind more driving and an additional change, maybe 2 nights Ennis or Doolin and 2 nights near Killarney.

Edit: and whether it makes more sense to do the marathon first (with jet lag) or last (after traveling), only you will know.