Zadar's old town is small enough to cross on foot in twenty minutes and rich enough to hold you for two or three days. The Roman forum, the round St Donatus, the cathedral, and the Land Gate sit within a few hundred metres of each other, and the waterfront with the Sea Organ and Sun Salutation is a short walk beyond.
Beyond the obvious sights, the town rewards wandering — narrow stone streets, fish markets, churches converted into bars, glimpses of the harbour through the gaps. Allow a half-day for the islands and the Kornati boat trips that leave from the marina.