pbiflyer

No car, so looks like the Grand Hotel would be the best option. Although the Portmarnock sounds very cool. It would be a Thursday night stay, so no nightclub worry.
Are taxis/ubers easy to get from there to the airport?

lwildernorva

I've always driven but taxis are generally easy to get in Ireland. I don't know the exact situation regarding Uber in Ireland, but I think the Irish government has done what they can to protect the local cab businesses. As their part of the bargain, the Irish cab companies offer prompt responses to service requests, unlike what occurs in many mid-sized American cities--one of the reasons that rideshare became so popular in the US.

Kgmm77

Uber is permitted but drivers must carry full taxi licences and drive fully marked cars with roof signs etc and are required to charge the standard taxi rate card (but you use the Uber app as normal). This somewhat negates the benefit of Uber. Free Now and Bolt operate in a similar manner (with more drivers signed up), but some drivers will use all 3 to drive business depending on fees etc. They are all now required to accept physical card payment for all fares but you can occasionally get the “machine is broken” excuse.

lamphs

I had a stopover at DUB. Stayed at the 'airport' Hilton, which does have a free airport shuttle. Depending on your tolerance for public transportation, the bus, either goes to downtown Dublin, or to Malahide. Note that the bus schedule is limited on Sundays, thus making Uber/taxi more expensive. I took the bus to Malahide as it is a small seaside town. I enjoyed walking around (and it was Christmas time). My previous stay in downtown Dublin, HI Exp, I took the train to Howth, another nice town to walk around and decent restaurants.

Finally, I could have gone to Belfast on a day trip via bus (and I think the train was the same length of time). I did take the bus from DUB (a decent motorcoach) and spent two nights. Any how, I think it was 2.5 hours either way. The bus drops off in downtown Belfast. In addition to DUB, I think the bus also continues to downtown Dublin.

fluffymitten

It's about a 2h drive down to Waterford which is a nice town to visit. I went there a couple of years ago because of the Waterford Walls project which is a street art initiative. Some fantastic artwork is available to view, some new (it's an annual thing) and some from previous years.
https://wallsproject.ie/

There's other stuff in the town to mooch around relating to the history of the area and the revived Waterford Crystal glassworks.

pbiflyer

I have been put in charge of the entertainment trip to Dublin with my colleagues. We had talked about a couple side trips thanks to suggestions here.
We have a full day available and a half day. Thanks to the awesome suggestions here, we have lots of options.
They have expressed interest in Belfast. We would likely take a train, if we go.
But it is a long way to go. A question - Is the train ride interesting ? Scenic? That would maybe tip the scales in favor of Belfast over the closer options suggested here.

pbiflyer

We ended up doing the Belfast trip, taking the train. Nice ride up and back. A bit of scenery, seeing the Irish Sea and some countryside. Did one of the black cab tours. Rainy so we didn't get to do much else.
One of our coworkers ended up doing Hawth the extra day he had and loved it.