Dublin or Shannon?

Ask yourself if you prefer to see the big city and surrounding area or more of the rugged countryside and smaller towns. Since you only have two or three days and no car your options are fewer. If you are big city people, opt for Dublin. You will have more than enough to see and do in just two or three days and you can use public transportation. If you prefer natural scenery and smaller towns opt for the west. Also keep in mind that you can fly into Kerry if you want to choose either the Dingle Peninsula or the Ring of Kerry. With your limited time I would choose one or the other. Both are spectacularly pretty. Ryanair flies from London to Kerry. I have flown Ryanair many times. I know that lots of people prefer not to fly with them but if you follow all of their guidelines and pack light I find them to be a viable option. Kerry is fairly close to either Dingle or Killarney or Kenmare, closer than Shannon, and may save you some time. You could hire a private driver to take you from whatever airport you choose to your desired town. Ask your B&B owner if they can suggest someone. They will also have contacts for half day or whole day tours of the area. Lots of scenic options if you fly into Shannon. I, personally, would go west and opt to see the scenic countryside and colorful towns, but I am not a big city person. Maybe someone on the forum can give you some bus and train options to consider.

If you do go to Dublin take advantage of excellent low cost tours that can take you to the Wicklow Mountains and Glendalough. The tour is excellent and will give you a chance to see some of beautiful wild Ireland and the incredible Monastic Ruins at Glendalough set in breathtaking country. Also a day trip from Dublin to the 5,000 year old burial tombs at Newgrange is spectacular as well......and its close. So even if you are city people give yourself the gift of seeing these magical spots in Ireland.

That being said, personally I'd opt for the West. Great advice on flying into Kerry. Private drivers and small tours (avoid the big bus tours - it's like being a cow in a cattle drive) are fantastic and not at all awkward. We are private, not super outgoing folks and within 5 minutes we felt like we were with family. The sights in the West, the insane beauty, ever present history and truly remarkably warm generous people make it our preferred destination on the planet.

You won't go wrong either way....it depends on what you personally prefer. Have a great trip....and if you choose Dublin be sure and head out to Wicklow/Gkendalough and/or Newgrange. Have a great trip !!!

Dublin for sure. Although you won't get a feel for Ireland as a whole by seeing Dublin, it will be much easier to navigate with such a short time frame.

Without a car you're pretty limited regarding what you can reasonably see and do in the brief time available to you.
Though flying into Shannon and trying to get down to Dingle is tempting, you really don't have time to waste just getting there and back from the airport.
Better (IMO) to keep it simple and stick to Dublin. The city itself is pleasant to explore, and as has already been mentioned the convenience of cheap day trips to Glendalough, Powerscourt, the Boyne Valley and Newgrange would help make the most of your discretionary time. Plus, there's always the quick day trip up to Belfast if you're interested in that.

I love western Ireland. You will still her Gaelic spoken and the countryside is beautiful. If you fly into Shannon, you could catch a bus to Galway. I know that Galway gets little respect on these forums, but it has decent pubs and food, a nice walking tour which provides interesting history and a museum. And it is also a center for tours. You could do an overnight tour to the Aran Islands, which I loved, head to the Burren, Cliffs of Moher or other destinations. These are typical bus tours (with the exception of the Aran Island ferry) but without a car, it is a way to see the major sites. The tours leave from just off Eyre Square in Galway, so if you base in a hotel near the square it will be easy.

Western Ireland and Dublin are two very different experiences. You just need to decide which holds more interest for you.

A PS. I do like the idea of a private driver if you can swing it. Some of the taxi drivers do private tours. We met a great one in Ennis (were just getting a ride to the airport, but he told us next time to hire him for the visit 😄). Ennis is just a short hop from the airport. From there you can also see Bunratty Castle. A bit touristy, but interesting. Think of a living history farm.