Trying to see Dingle

Unfortunately, you are adding one condition after another that makes it harder to do what you want to do...

• Just 7 days in Ireland (Reality check: Do you really have 7 full days there on the ground? Hopefully you are not counting the day you arrive, nor the day you leave...)
• Can't extend the trip.
• First 2 nights are in Dublin.
• Dublin hotel rez can't be changed.
• Won't be renting a car.

Ireland is "bigger" than many first time visitors expect. It takes some time to get all the way from Dublin to Dingle (that's about as far away as two points can be in Ireland). It's going to be hard to do that given your other constraints, unless you make the trip to/from Dingle and let go of some/most other things.

There are flights between Dublin and Shannon (nearer, but still not super-close to Dingle), so that's an option (though you would probably need to have a car rental to get from Shannon to Dingle and back on your own schedule). No matter how you slice it, you will consume most of a day getting to Dingle, and another day getting back. You can do the math - with the number of days you have, spending two of them crossing the country may not be a great choice, but it's your trip.

It's theoretically possible, but would be difficult given your other constraints. Dingle is great, but might not be worth the tradeoffs.

Cross Dingle off your list. The time spent getting there on public transport will not be worth your while on such a limited trip.

There are some other great alternatives. You could consider a few days in Northern Ireland. I found public transit to be fairly user friendly there. You can take the train to Belfast and enjoy the sights (including the Titanic Experience which is amazing). Then take the train to Coleraine and walk through the train station to the buses. The Causeway Rambler https://www.causewaycoastway.com/travel/causeway-buses.php will take you to the main sites along the Antrim Coast. I personally love the Bayview Hotel in Port Ballintrae (bus stops outside) but there are other options in Portrush or Bushmills.

Here is another possible alternative easily done on public transport. Take the train to Galway. You can explore Galway and the Aran Islands. The ferries run a shuttle bus from downtown Galway out to the ferry dock for the Aran Islands. You can see beautiful views of cliffs here. It is also possible to daytrip to the Cliffs of Mohr.

These aren't Dingle, but they are beautiful and they are accessible. With one week and on public transport, you need to choose your destinations carefully.

From Dublin, there is a bus that takes 8.5 hours and two transfers to Dingle. The Dingle Peninsula is best toured by vehicle. We were fortunate to have a car and a glorious sunny day when we did the Dingle Peninsula but if it’s rainy/foggy would you find it worth a 7 or 8 hour trip each way (basically two full days) when your time is so limited in Ireland. There are tours you can take from Dingle if you are willing to sacrifice that much time out of your seven days in Ireland.

There are two direct flights per day on Ryanair between Dublin and the Kerry Airport near Killarny. From there you can book day trips around the ROK, Dingle, and visit the National Park at your leisure, returning to Dublin via the return flight when you're done.

We found a three day coach tour to Dingle from London which seems to pack alot in -- includes many sights along the way with two nights in Dingle to get the feeling of the place. It seems they usually depart on Mondays so not sure if that could work for you. We'll be doing this in August. https://www.rabbies.com/en/ireland-tours/from-dublin/3-day-tours/dingle-killarney-wild-atlantic-way-3-day-tour