The Baie de Somme's boat operator runs two vessels: the Commandant Charcot V from Le Crotoy, and a sister boat from Saint-Valéry on the far shore. The Crotoy trips head out into the estuary on the incoming tide, with commentary on the bay, the shifting channels and the birdlife, and a reasonable chance of seals on the banks near the mouth.
Sailings are dictated entirely by the tide — the bay is dry for much of the day — so the timetable changes daily and there are days with no departures at all. The ticket office is on the Quai Courbet next to the fish hall, opening an hour before the first sailing, and booking at least 48 hours ahead is advised in summer.