Five Best: Private Islands

Get far from the madding crowd and live like a billionaire on the world's most exclusive islands. Aoife O'Riordain joins the international jet set

Turtle Island Fiji

Turtle Island, Fiji

This 500-acre speck in Fiji's Yasawas archipelago was the location for the film "The Blue Lagoon". Since buying Turtle Island in 1972, owner Richard Evanson has replanted over 300,000 indigenous trees and instigated a protection programme for endangered green and hawksbill turtles. He also established the Yasawas Community Foundation that has recently opened the island's first secondary school. Only 14 couples can share Turtle Island at any one time, staying in traditional thatched bures. The island's 14 pristine beaches also provide ample space for bona fide Robinson Crusoe experiences, albeit with a gourmet picnic hamper and champagne glass in hand.

Double rooms on Turtle Island (00 61 3 98 23 8300; www.turtlefiji.com.au) start from US$1,850 (£1,322) per couple, per day on an all-inclusive basis. Minimum stay six nights

Mnemba Island, Tanzania

For barefoot, sand-between-your-toes luxury it would take a lot to improve upon Mnemba Island, owned by Conservation Corporation Africa. Even arriving at the resort involves wading through calf-depth seas the temperature of bath water. A little under three miles off the north-eastern coast of Zanzibar, Mnemba is surrounded by coral reefs, the impossibly turquoise waters of the Indian Ocean and fringed with some of the whitest sand imaginable. Its 10 beach bandas are the height of castaway chic, constructed from hand-woven Zanzibari palm matting. The resort reopened just two weeks ago, following a complete overhaul, and each banda is now raised on a platform over the beach, with direct access to the sea, and with maximum privacy guaranteed.

Double rooms at Mnemba Island Lodge, Zanzibar (00 27 11 809 4300; www.ccafrica.com) start from US$650 (£406) per person, based on two sharing, including full-board accommodation, drinks and snorkelling

Wilson Island, Australia

Just north of the Tropic of Capricorn, Wilson Island is a tiny five-acre blip of coral on Australia's Great Barrier Reef. Owned by P&O Resorts, the emphasis is on sustainable eco-friendly tourism designed to protect the island's fragile environment. Wilson Island is considered so precious that there isn't even a jetty and only 12 guests can stay at any one time, sleeping in specially designed solar-powered, luxury tents. Visitors are also encouraged to forgo their hammocks and learn about their surroundings; the island is both a national park and an important breeding ground for birds and turtles. Other attractions include reef walks, birdwatching, stargazing and superlative snorkelling.

The Wilson Island Experience is available from 14 November (020-7805 3875; www.wilsonisland.com) and costs AUS$1,690 (£646) per person, based on two sharing. This includes two nights on nearby Heron Island and three nights on Wilson Island, all meals, drinks and transfers

Necker Island, British Virgin Islands

Richard Branson's first view of his 74-acre British Virgin Island was from high above in a helicopter and it's no surprise to learn it was love at first sight. A short hop from both Tortola and Virgin Gorda, Necker Island offers seclusion and luxury in equal measure. Despite its location in the middle of the Caribbean, Necker's four houses follow a decidedly Balinese theme. The main house perches on the island's highest point and commands magnificent views of the Caribbean and there are three smaller cottages dotted around in the lush vegetation - Bali Hi, Bali Lo and Bali Cliff. All also have use of Necker's latest addition, the Bali Leha spa, built into a cliff overlooking the sea. Rental starts from $22,500 (£13,750) per day for up to 14 guests and $36,000 (£22,500) for up to 26 guest. There are also "celebration" weeks on selected dates iduring the year, when couples can stay for seven nights from $18,000 (£11,250), including all food and drinks, activities and transfers from Virgin Gorda or Beef Island.

Necker Island (020-7227 6969; www.necker.com)

Waterford Castle, Ireland

Waterford Castle is a 16th-century stately pile occupying its own 310-acre island on the River Suir, three miles outside Waterford on Ireland's south coast. The castle was enlarged in the 19th century, but sections date from the 11th century - it opened as a hotel in 1988. There is also an 18-hole golf course and guests can learn clay-pigeon shooting and archery.

Double rooms (00 353 51 878 203; www.waterfordcastle.com) start from €330 (£235) without breakfast, but special offers are often available