This is Picardy coast country, and the food on St-Valéry's plates comes mostly from the bay and the marshes around it: mussels and cockles fresh from the sandflats, fish from the small inshore boats that work out of the harbour, and lamb from the prés-salés, the salt-meadow pastures grazed by sheep that give the meat a distinctive savour.
Order moules in season — September to April for the local moules de bouchot — and ask about ficelle picarde, a regional speciality of crêpes filled with ham and mushrooms in a creamy béchamel. Salicorne, the salt-marsh samphire harvested in the bay, turns up in summer as a tart green vegetable alongside fish.
Most of the restaurants and bistros are along the Quai du Romerel and the streets just behind it; for something quieter, walk up into the old town. Reservations are wise on summer weekends and during the school holidays, when the bay fills up with visitors from Paris and Lille.