Take the steps down to Puntulina's terrace, where you can enjoy a glass of Istrian or other Croatian wine in a pleasant atmosphere yards from the sea, with light pop music setting the tone, plus amazing sunsets. And, yes, you can take a few more steps down if you wish, to the rocks, and take a dip before or after being served—for this is where Rovinj's free, public swimming area begins. It's not especially a "night" spot, so you may wish to confine your wine-sipping to daylight hours. There's also an excellent restaurant on the upper level.
Sv Križ 38, Rovinj, 52210, Croatia