St-Valéry is well placed for a wider exploration of the Baie de Somme and the Picardy coast. The heritage railway is itself a day trip — the run across to Le Crotoy on the north shore takes about an hour and lands you in a smaller fishing village with a long beach and a row of seafood cafés.
Cayeux-sur-Mer, on the open Channel coast about 15 km south, is famous for its three-kilometre boardwalk lined with painted beach huts. The Pointe du Hourdel is a short detour from Cayeux and the best spot for seal watching at low tide.
Inland, Abbeville (25 km east) has the surviving facade of the Gothic collegiate church of Saint-Vulfran, badly damaged in 1940 but still worth seeing. Further south, the gardens at the Château de Bagatelle are open to visitors in summer. For something more sobering, the World War I battlefields of the Somme — Beaumont-Hamel, Thiepval, the Newfoundland Memorial — are a 90-minute drive inland and make a substantial day out.