The kids will sleep soundly after frolicking by the seaside at Plage de la Cabane. Search for cute critters like crabs and snails, stick a toe in the water or toss a ball around!
To explore this stretch of coastline, head to L'Épine. There are loads of other interesting attractions in the area, such as Chateau de Noirmoutier, Bois de la Chaize Beach, and La Gueriniere Beach.