Bar do Porto sits near the old port area at the edge of Praia Grande, a relaxed waterfront bar that's popular for afternoon drinks and early evening beers before the reggae bars get going. The view across the bay is good at sunset, the caipirinha — Brazil's national cocktail of cachaça, lime, and sugar — is made generously, and the snacks include good fried shrimp and crab cakes.
It's a good place to start the evening: come around 6pm, watch the sun go down over the bay, have a couple of drinks, then walk up into the old town to find dinner and music. The staff are friendly and used to tourists, which can be a relief if your Portuguese is limited.