Howth is a fishing village on a hill that happens to sit at the mouth of Dublin Bay, and the walk does both halves: the working harbour at sea level, then the cliff path round the Head with the open water on one side and heather on the other. It is the best half-day Dublin keeps within thirty minutes of the city centre.
Seven and a half kilometres, best on a clear morning. The DART drops you at the harbour — walk the West Pier first, past the trawlers and the seals, before the gulls and the day-trippers arrive. Out to the East Pier lighthouse, then up onto the cliff path at Balscadden, where Ireland's Eye sits offshore and the sea takes over.
Round the Nose of Howth the path turns south and the whole Irish Sea opens. Keep going to the high ground above the Baily Lighthouse — white tower, black rock, the entrance to the bay — which is the view the walk is built around. From there climb to the summit for the heather and the Wicklow hills across the water, then drop back down to the village. The Summit Inn, a pint, and the DART home.