This leg follows the Médoc coastline, a string of long ocean beaches sheltered by the dune line and the pine forest of the Landes de Gascogne. The route runs mostly through forest and is sheltered from the wind, with regular seaside towns to restock (Montalivet, Hourtin, Lacanau).
Approaching Arcachon Bay brings a change of scenery: you leave the straight ocean coastline for the sheltered bay, its oyster beds and typical oyster-farming villages (Le Canon, L’Herbe) on the Cap-Ferret side.
Arcachon itself, with the Dune du Pilat close by, is worth a night or two before heading south into the Landes.
Distances shown are indicative; several route variants exist around the bay (north shore via Cap-Ferret, or a more direct south shore path).