Dublins city centre is compact and therefore ideal to walk around in. For example a walk from O’Connell Street to St Stephens Green would only take about 15 minutes.
If you fancy a days leisurely walking while catching some sights, try this: Dublin Castle to Trinity College then to the National Museum and finish at the National Gallery (or in reverse). This walk (not including visiting time of course) would less than an hour and is a lovely way to catch some of the streets of Dublin.
