Guide or Travel Company for tours in Dublin

We took two tours, both were excellent.

The Mary Gibbons tour to Newgrange and Hill of Tara

And the Rural Pub Tour ( simply called Rural Pub Tours)

Is there anything specific you're interested in seeing?

For general stuff, or just a place to start, I highly recommend the Hop On, Hop Off bus in Dublin. They are clean, comfortable, and the commentary is live. The route is quite long, so you'll see parts of the city you may not otherwise visit. I've used the HOHO buses all over the world, and Dublin's was - by far - my favorite.

we just arrived from Ireland 3 days ago. we stayed in Ireland for 11 days, visiting 2 towns before our last stop being Dublin. we joined the 3-hour free walking tour (only tips) sponsored by the sandeman tours in Dublin. this was recommended to us by the tourist info office. it was excellent; one learns some irish history, the stories behind some of the sights our guide took us to, some bit of irish culture, etc. etc. I highly recommend it.