This large park in Dublin has a number of waymarked walking trails to try. Highlights in the park include a nice surfaced footpath running along the lakes and the River Poddle.
There's over 300 acres to explore on a network of trails including a Fitwalk Circuit and three colour coded trails. In the southern end of the park you'll find the impressive Millenium Landmark Structure and the PACT woodland. At the northern end are the waterside trails along the lakes and river where you can look out for various waterfowl.
Tymon Park is the second largest park in Dublin. You can continue your exercise in the larger Phoenix Park which is located a couple of miles west of the Dublin city centre. There's more good walking trails here with large areas of grassland and attractive tree-lined avenues.
Also near the city you can try the popular Howth Cliff Walk.