You can stroll along Rovinj Harbour for relaxing water views when you're in Old Town Rovinj. If you carry on walking you'll get to Rovinj Marina for some more water views.
Katarina Island is worth a visit, located 0.6 mi (1 km) from central Rovinj. Why not take a stroll along the port and watch the sunset while you're here?
After visiting St. Euphemia's Church, make a plan to see the other sights and activities in Rovinj. While you're in the area, stroll along the waterfront.