Arraial do Cabo

The water here is unreal, properly turquoise, and the whole town is built around getting you out into it. Stay in Arraial rather than Cabo Frio - every boat leaves from Praia dos Anjos and you want to be walking distance from it. Climb the hill behind the town for the view down onto Prainhas do Pontal do Atalaia, all cactus and white sand and boats sitting on their own shadows, and go back up in the evening. Four days felt about right and I would go again tomorrow.