There is a daily ferry to Venice from the harbour in Rovinj. The ferry takes about 2 hours and takes you to almost the centre of Venice. There are also taxi boats and excursions to St Katherine's Island, in the harbour.
The old town is best explored on foot. Worth seeing are the original entrance into the city, the Balbi Arch; the market at Valdibora; the cathedral of Sv. Euphemia; the artists' street of Grisia, described as "Rovinj's Montmartre"; and the harbour in the centre of the town.
