Wicklow - for hiking in the Wicklow mountains - try any combination of the Walk in the Garden caches 

2 A Walk in the Garden-Kilbride Circuit

North of city - Howth - nice spot with a lot of nice hides and views - can be reached by DART train from city centre.

Aideen's Dolmen 

Short Multi near city centre. Most visited multi in Dublin over the last 12 months. Smashing sculpture -well worth seeing, dedicated to a particularly sad piece our Ireland's history. 

An Gorta Mór (The Great Famine)

City Centre - have to add this one cause it's mine ;) Deceptively big church - with relic of St.Valentine 

Be My Valentine

Wicklow - worth the climb up to this one if you're in the area picking up Europe's First

Bray Head

A powertrail starting from this one - although you could just as easily start from Blackrock DART station and  #6 to #1 to #7 to #41 :) Some great views along the walk. Enjoy 

BRPT - 01 Idrone Terrace

BRPT - 06 Idrone Terrace

Wicklow - should be done with The Wanderer and Europe's First -great 
views - need a head for heights. 

Brunel's Folly

North of city - good twist at cache location. 

Define Geocaching

City Centre -Nice short multi around Stephens Green

Dublin Can Be Heaven

Wicklow - This is a must have for cacher visitors to Ireland.
Area can be reached by DART train from city centre

Europe's First

Firefly series - #10 - Shepherd Book

Hello, can I talk to the Cache?

Dublin & Wicklow - I'm adding this cache to this bookmark list because I believe it is one of the very best in Ireland. 
Probably not a runner for a tourist as you need to find 2 other caches
 (Confidential : GC2HQGK - in the Phoenix Park & then Top Secret :  GC2HPB3 - up near 3 Rock Mountain )   & solve the puzzles first - but if you can manage it I guarantee you will enjoy all 3. 

Highly Classified

North of city - Howth - many nice caches & walks in this area - can be reached by DART from City , good for a days outing from the city. Great views from Howth Head. 

Howth Cliff Walk - Piper's Gut

Dublin city - Nice short multi around an historical area. 

Jailhouse Rock

Glendalough - can be combined with a nice days hiking around the area - many other caches here too. 

Kevin's Dental Work

City Centre - Nice short multi to 3 nice spots (close together)  in city centre

Learning Money and Seafood

City Centre - quite long multi - brings you to a few nice pubs. Takes time

Northside Pub Crawl

Good place to get off the DART and start the BPT here. Go #6 to #1 .... & then to #7 and to infinity ...... or to #41 as I write ... plenty of other ones to pick up on the way too. 
Not sure of the distance although a cacher said on the FB page lately they spent 10 hours doing the trail. 
Some fab views along the way

Dublin- cache info for tourists.list-details-1wr9x6v{text-transform:uppercase;font-size:12px;}@media screen and (min-width: 600px){.list-details-1wr9x6v{font-size:1.25rem;}}.list-details-1wr9x6v.shareable{color:#87705a;}.list-details-1wr9x6v.public{color:#00b265;}Public

Dublin- cache info for touristsPublic