Maeil Olle Market is Seogwipo's everyday market and the easiest place in town to graze. Stalls sell citrus, seafood, black-pork snacks, tteokbokki, fried foods, and boxes of Jeju produce aimed at visitors flying home.
Come hungry rather than treating it as a shopping errand. It is central, open into the evening, and a useful fallback when you do not want a formal restaurant.