Contemplating committing yourself—and your money—to island ownership? Sample the solitary life first by renting one of these

Indigo Island, Bahamas
Surrounded by several uninhabited islands in the Exuma chain, Indigo can accommodate up to 12 guests in its four luxe villas. The two hilltop pavilions are decorated in vibrant colors and with exotic artifacts, the Beach House sits on its own private cove, and the more formal Indigo House is filled with Indian and African antiques and features floor-to-ceiling windows. There's also a tennis court, a media room, and a marina stocked with equipment for every imaginable water sport.
When to go: year-round (954-525-5101; www.indigoisland.com; $26,000 per night for up to eight guests, $2,000 for each additional guest).

Cayo Espanto, Belize
This island resort near the Belize Barrier Reef has five vast oceanfront villas (the smallest measures 1,100 square feet, the largest 2,400); four have their own plunge pools, three have private docks. Chefs prepare gourmet fare, and activities include fly-fishing, scuba diving on the reef, snorkeling in the nearby marine park, bird-watching, and indulging in the many spa treatments.
When to go: year-round (888-666-4282; www.aprivateisland.com; $9,000 per night including meals five-night minimum).

Necker Island, British Virgin Islands
For two decades, Richard Branson's 74-acre Balinese-inspired retreat has cosseted privacy-hungry celebrities such as Mariah Carey and Princess Diana. Guests sleep in the Great House, which has ten bedrooms and a roof-top terrace, or in one of the three thatch-roofed cottages perched high above the sea. The list of activities includes horseback riding, tennis, sailing, snorkeling, diving (coral reefs surround the island), and lounging around the two pools (alas, only one has a swim-up bar). Rates vary within season.
When to go: year-round (732-473-9982; www.neckerisland.com; $22,500-$40,000 per night, including meals).

Sleepy Cove Island, Nova Scotia, Canada
This densely wooded island (owned by Bill Gates) in the middle of Shubenacadie Grand Lake is a 30-minute boat ride from Halifax. The one fairly rustic cabin—big enough for two adults and two children—has electricity, hot water, and a deck overlooking the forest. Guests prepare their own meals, so bring groceries—or your fishing rod.
When to go: May through October (49-40-33-00-00; www.vladi-private-islands.de; $135 per night, plus a $125 housekeeping fee).

Dolphin Island, Fiji
Owned and operated by the winning team behind New Zealand's luxurious Huka Lodge, the eight-acre Dolphin Island is a sophisticated hideaway 15 minutes by ferry from the main island of Viti Levu. Sleeping quarters are in a lavishly decorated two-bedroom open-air bungalow; the dining room, where the cook prepares traditional Fijian fare, is in a similar structure just steps away from the manicured lawn. Snorkeling gear, kayaks, and a catamaran are all available.
When to go: May through October are the driest months (64-7-378-5791; www.dolphinislandfiji.co.nz; $1,630 per night for two, including meals; four-night minimum).