1. Bawah Island, Indonesia

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Five jungle-nettled islands with eco credentials surging from the waters of a marine conservation area on the isolated Anambas archipelago. The journey there – a ferry then a seaplane from Singapore, across the South China Sea – may be epic but the reward is three sheltered lagoons where colourful parrot fish dart by day and fruit bats swirl at night. Guests can paddle-board between the 13 private beaches and swim with turtles, and the resort goes to great lengths to protect its coral reef. Water is bottled on-site, and furnishings are hewn from flotsam.

2. Soneva Fushi, Maldives

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It’s all about delivering big experiences with a small footprint at the resort that invented barefoot luxury; indeed, guests are still encouraged to surrender their shoes to a drawstring bag on arrival. Some villas have swimming pools with sunken dining tables, but the resort also has its own vegetable garden, recycling factory and solar power plant. The outdoor cinema uses personal headphones so as not to disturb the island wildlife, and guests can enjoy unpolluted skies.

3. The Brando, French Polynesia

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Destinations don’t get more far-flung than the late Marlon Brando’s private island in the middle of the Pacific Ocean, where Pippa Middleton honeymooned and Barack Obama is said to have penned his memoirs in secrecy. Guests can enjoy massages and scented baths in the canopies. They can also relax in the knowledge that this slice of paradise is being passionately protected: seawater powers the air conditioning, and a coconut-oil station provides more than half of the resort’s energy needs.

4. Fregate Island Private, Seychelles

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This Indian Ocean hideaway has – among other things – saved the world’s largest species of giant millipedes from extinction. Wildlife initiatives are central to Fregate Island’s mission, whether it is boosting the local population of magpie robins (one of the world’s rarest birds) or protecting the habitat of Aldabra giant tortoises, which roam the beaches freely. It is super-exclusive, with just 16 villas - each with its own butler and infinity pool.

5. Song Saa, Cambodia

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A twin-set of frangipani-framed land masses in the remote Koh Rong archipelago, a Bond-style speedboat ride from Cambodia. These two islands shaped like mismatching earrings offer plenty of five-star bling – the one or two-bedroom villas all have plunge pools and muslin-draped four-posters; and there is an overwater restaurant. Yet the conservation efforts are what make the place really stand out from its competitors. The all-inclusive resort has been transformed into a pristine, protected “reserve” with its own resident marine biologist. Guests can explore the mangroves, hike the rainforests and go snorkelling with seahorses.