Start at Narodni trg (People’s Square), the natural civic heart of the Old Town. Come around 8:30–9:00, when the cafés are lively but the square is not yet crowded, and take in the Venetian-era City Loggia, City Guard, and clock tower. Allow about 30 minutes, then walk five minutes along Široka ulica (Kalelarga) toward the Roman Forum and Church of St. Donatus. The Forum is freely explored outdoors; St. Donatus usually opens from roughly 9:00, with entry commonly around €5, though summer hours and prices can change. Give this area an hour, looking beyond the postcard view for fragments of Roman columns reused in the medieval buildings.
Continue a short walk to the Museum of Ancient Glass, housed in the historic Cosmacendi Palace. It is an excellent one-hour stop, particularly for the live glassblowing demonstrations; allow approximately €6–8 for admission and check the day’s demonstration times at the entrance. The museum is generally open through the morning and afternoon in summer, but arriving before lunch is wise. For lunch, walk about 10 minutes southeast to Foša Restaurant, beside the small Foša harbor and the old city walls. Reserve ahead for a waterfront table; expect approximately €35–60 per person for seafood, and allow 1½ hours rather than rushing the meal.
After lunch, take an unhurried walk back through the Old Town and toward the Riva. Reach the Sea Organ and Greeting to the Sun around 17:00–18:00, when the waterfront light is softer and the sea organ’s tones are easiest to appreciate without the midday heat. Both installations are free and always accessible. From there, follow the waterfront or take a short taxi ride—about 2 km, usually 5–10 minutes depending on traffic—to Kolovare Beach. It is Zadar’s most convenient city beach, with pebbles, concrete sunbathing areas, showers, and nearby cafés; bring water shoes and a towel, and avoid leaving valuables unattended. Spend up to two hours swimming and relaxing, then return toward the Old Town for sunset, allowing roughly 20–30 minutes on foot or 10 minutes by taxi.