Many people's favourite spot on the whole coast: a perfect sheltered bay of impossibly clear water, a tumble of ochre houses, a tiny sand-and-shingle beach, and a citadel — all a 10-minute train ride away. There's little to 'do' beyond swim, eat and wander, which is precisely the point; that's also why it's a half-day, not a full one.
Villefranche-sur-Mer's bay is one of the deepest natural harbours on the Mediterranean coast; the train from Nice takes ~6 minutes (one stop). · niceandbeyond.com
Its main beach, Plage des Marinières, runs along the bay just below the train station, with calm sheltered water. · niceandbeyond.com