For your visit one day may be enough.
Distances are walkable in all instances.
Worthy attractions: (viewed all from outside only) Trinity College; Dublin Castle; Christ Church cathedral.
Left for another visit: Book of Kells; National Museum; St Patrick’s cathedral.
Last visit: March 2017.

Dublin is a pleasant enough city but not too remarkable. Lovers of Irish beer will find a good measure of delight in bar-hopping. For the rest of us, there are not much in the way of major sights or magnificent public spaces to sustain interest for any protracted duration of time.
Things to See
Dublin city center is relatively small, with Grafton Street pedestrian shopping area being its focal point. This area is continuously bustling, while a few blocks in almost any direction would take you to considerably sleepier areas. The most famous concentration of pubs is nearby in Temple Bar ♥ (this is the name of the area on the bank of River Liffey, although there is also one bar that appropriates the name for itself); it gets crazily crowded on most nights.
The architecture is dominated by the four-story, flat-façade brownstones, which are fairly unexceptional in their uniformity. Pedestrian central streets inject some variety into that. There are a few attractive churches (which reputedly are rather unembellished on the interior), but also a fair share of plain modern boxes.
My time in Dublin did not allow for in-depth exploration of most important landmarks, but I strolled through and around Trinity College ♥ and Dublin Castle ♥, and came by Christ Church Cathedral.
St Stephen’s Green ♥ is a beautiful central park, with a pond, lots of greenery and a dozen or so memorials to famous Irishmen. Merrion Square Park looks far less manicured and far more conducive to reflections in solitude. Its fences serve as display cases for dozens of painters who offer their creations for sale on weekends. The fun monument to Oscar Wilde ♥ is found in one corner of the park.
Further afield
Glendalough ♥♥, about 30 miles south of Dublin, is a part of Wicklow Mountains National Park centered on a ruined monastic village. The monastery and its round tower is a popular attraction in itself, but there are also miles of walking trails of varying difficulty around the hills and lakes.
The peninsula suburb of Howth, 10 miles northeast of Dublin center, is a charming community, hosting a number of good seafood eateries.
Even more charming is coast-side Malahide ♥♥, 10 miles north of Dublin. There is an impressive castle and gardens ♥, a pretty coastal drive in both directions, and an atmospheric town center.
World Heritage sites of Brú na Bóinne ♥♥ (the main one is called Newgrange, there are also Dowth and Knowth) are within easy driving distance from Dublin. Archaeological sites frequently leave a lot to imagination, but the passage mound at Newgrange is plainly mind-blowing, considering its origin and purpose.
Places to Eat
The crowd wisdom of TripAdvisor nowadays makes selection of the most suitable places to eat significantly more informed. Here are short notes of our culinary experiences in Dublin to supplement that.
Places visited in Spring of 2017.
Locks ♥♥, on the canal in Portobello neighborhood – small menu of modern takes on Irish staples, French-size portions, stylish setting, very tasty food, nicest staff.
Boqueria ♥♥, in Howth – creative tapas fusion menu, country inn atmosphere, almost excellent service (got slower as more people came in).
Nautilus ♥♥, in Malahide – on the second floor of a waterfront building, with nice views of the bay; very pleasant service, brilliant and well-presented food, but a bit on expensive side.
Pub Mulligan’s Grocer ♥, in Stoneybatter district – not a big food menu, but several nice traditional choices; good understated vibe.
Far back from Spring of 2008.
Thai restaurant Diep Le Shaker ♥♥ – fashionable and hip, youngish clientele, popular. Great authentic food and a pretty good wine selection.
Hugo’s ♥♥, on Merrion Row not far from the corner of St Stephen’s Green – international menu, with plates representative of Spanish, Irish, French, South American and other cuisines; expertly comprehensive wine selection. The interior is a bit on the old-fashioned posh-club side, quite pleasant.
Up the road from Glendalough visitor center, Wicklow Heather ♥ serves contemporary and traditional Irish food in a sophisticated restaurant environment, masquerading as a country inn from the exterior.