Porquerolles, France
Across the water from the glitz and spritz of the Cote d’Azur, Porquerolles is a lemon-slice of timeless Riviera romance. No high-rollers, no high-heeled beach clubs – just five square miles of protected Mediterranean paradise that’s part conservation area, part privately owned. There’s little development to spoil it, just a sleepy 19th-century village and a rather lovely hotel, Le Mas du Langoustier (langoustier.com), whose blue shutters, pink bougainvillea and terracotta walls make a colourful splash amid the evergreens – though, this being the Cote d’Azur, it does have a Michelin-starred restaurant. Hire a boat to seek out quiet coves, or hop on a bike and cycle paths scented with eucalyptus, pine and wild thyme.

Ons Island, Spain
Illa de Ons is the best-kept secret in Galicia, which is itself the best-kept secret in Spain. That’s next-level secret stuff. And once you have been entrusted with the knowledge, there’s still the problem of access – visitor passes and boats are limited. All of which makes actually getting to Ons a triumph even before you’ve skipped barefoot along the driftwood boardwalk to the beach, whose electric-blue waters are invigoratingly fresh. Walk a little further, along the sandy track to Melide beach, and it’s a good bet you’ll find a stretch of white seashell-sand to yourself. The island is part of a national park and highly protected: no cars, no bins, no hotels – though you can camp there in safari tents (campingisladeons.com). When all the daytrippers have caught the last boat home, it’s like having the secret all to yourself.

Hydra, Greece
Hydra has always been a bolthole for artists and poets, free-thinkers and free-lovers, ever since Sophia Loren filmed here in 1957 and Leonard Cohen bought a house in the 1960s – Henry Miller, Le Corbusier, Lawrence Durrell; Beatles, Stones, Pink Floyd; heads of state and art collectors. No matter who visits, they get around the same way: by donkey, boat, or their own two feet, up and down the steep, cobbled streets of the sunshine-toned town, or along mule tracks to pebble beaches – a bicycle would be risibly ill-suited to such terrain. So many artists means an abundance of artfully restored buildings to stay in. Try Miranda Hotel, a former sea captain’s mansion (mirandahotel.gr); or the 18th-century blue-and-white Orloff (orloff.gr).

Alicudi, Italy
Flung off Sicily’s west coast, this conical little island is the most unspoiled and unpolished of the Aeolians. Cacti and olive trees grow on its volcanic slopes; its shores are wild, waters clear and pale as opal. At the quay, fishermen still sell their catch in the mornings, and donkeys pick up baggage off the boats. At night, there are no street lamps (no streets, even) and the skies are bright with stars. There’s very little to do – and that’s really the point of Alicudi.

Cavallo, France
So bewitching is this tiny Corsican outpost that it has been coveted and fought over by wayfarers since Roman times. In the 1960s, a Parisian disco king bought it and turned it into a Mediterranean utopia for his starry friends, who came to eat lobster and dance on Cavallo’s beaches, which remain its biggest lure: pristine croissants of champagne-coloured sand, curving between wild maquis and the most triumphantly turquoise, limpid waters in Europe, and bookmarked by great Seychellois boulders. Avoid July and August, when the place jostles with Italian billionaires, and instead come in June or September. There’s one hotel (hoteldespecheurs.com); or rent one of Savin Couëlle’s trippy ’60s villas (cavalloisland.com).

Lopud, Croatia
The glamour of Hvar hasn’t made it down the Dalmatian Coast to Lopud. It’s as lo-fi as it gets. A harbour village, a cluster of terracotta roofed stone buildings, drowses in permanent siesta. Sling on a knapsack and follow the only road up hill and down to sandy Sunj on the other side of the island, where the sea is warm and a couple of bars serve cocktails and fried fish; fortification for the walk home. Digs are limited. If you’re going all out, Lopud 1483 is out of this world, an ancient monastery restored by an art collector and filled with her incredible collection (lopud1483.com). Otherwise, villalopud.com is down-to-earth lovely, and has a pool.
Laura Fowler is a travel writer and contributing editor for Condé Nast Traveller, The Telegraph and Cereal magazine