Baiona is a serious seafood town. The harbour provides mussels, barnacles (percebes), razor clams, and whatever fish came in that morning. The old town's waterfront restaurants are uniformly oriented toward seafood, with a few places doing a perfectly decent menú del día for a reasonable price at lunch.
Percebes — goose barnacles — are a Galician specialty and Baiona is one of the better places to try them. They are expensive, require no skill to prepare (they are simply boiled in salted water), and taste intensely of the sea. Order a small ración to start.