Roquebrune-Cap-Martin, Plage de la Buse, a couple of kilometres east of Monaco and connected by a pleasant, coastal hiking trail, the Sentier des Douaniers.
This fine, though partly pebbly public beach offers a wide sweep of shallow water, an excellent beach café that also rents kayaks and is just 100m from the car park at Roquebrune train station.
Cap d’Ail, Mala Plage, a few minutes west of Monaco is a good size and has a rarely crowded public beach zone perfectly embraced by cliffs, with marine activities rentals and a fine restaurant.
Access is via a steep – though agreeable – 10 minute hike down from Avenue Princesse Grace. Take either a bus to the Beaverbrook stop or drive and park in the Cap d’Ail car park, walking down Ave. Francois de May until you see brown signs indicating the way to the beach.
Saint-Jean-Cap-Ferrat, Paloma Plage. A few minutes walk from Saint-Jean village, Paloma sits on a calm, sandy bay lapped by clear waters. There is a private beach club area and a pricey café/restaurant as well as the public beach. When swimming becomes a bore take a hike along the delightful little trail Sentier Edmund Davies around the Paloma Point headland.
Villefranche, Plage de Passable, a sheltered stretch of pebbly bay popular with local families in-the-know, Passable has a good restaurant and is the starting point for a terrific 4km Cap Ferrat walking trail around the Ferrat peninsula.
Cap d’Antibes (Antibes‘ very exclusive peninsula), Plage de la Garoupe is the place for wealth-spotting, just a Bentley waft from possibly the Riviera’s best hotel, the Eden Roc; La Garoupe’s public area is limited by a pricey beach club but the sand is soft, the rocks interesting if there are no jellies at home, the views of Antibes coast spectacular and the snorkelling pretty good. Furthermore, there’s a really fine little walk around the shore of the Cap, taking between one and two hours.