Start at the plage des Graniers, a narrow strip of sand tucked below the Citadelle, just past the Cimetière Marin. The water here is the kind of clear that makes you stop walking. The beach itself is short, a few dozen metres at most. But that's not really the point.
From the Graniers, the path hugs the rocky coastline of the peninsula, climbing and dipping without ever getting brutal about it. The views open up quickly: open sea, and on a clear day the islands sitting low on the horizon. Small, mostly quiet coves break up the walk at intervals, the sort of places where you can sit on a rock and eat a peach in peace.
The trail runs all year and costs nothing. Off-season, it's nearly empty. A ponant wind in the pines, waves on the rocks, the occasional fisherman. Come July, the section closest to the village fills up, but the stretch out of the Graniers stays relatively calm by Saint-Tropez standards.
Access is via the chemin des Graniers, after the marine cemetery at the edge of the village. A small car park sits right there. Dogs welcome on a lead.