Dunbar Rock, Honduras
In the eastern corner of Honduras's Bay Islands chain, the whitewashed, six-bedroom Villa at Dunbar Rock sits atop a 2,000-square-foot granite islet. Balconies encircle each of the three floors, and up to 12 guests can take in sweeping 20-mile views of the Caribbean on one side and, on the other, Guanaja island, an easy swim or 90-second boat ride away. A staircase clinging to the rock drops down to your dock, and a cook motors in three times a day to prepare fresh-from-the-ocean lobster or tuna. The villa is a satellite of Guanaja's Nautilus Dive Resort, a five-room, two-apartment setup with a newly renovated dive shop—just give a ring and caretaker/dive master Denis Midence will zoom over in a skiff. Midence, who is PADI certified, stands ready to ferry guests on two scuba dives a day, plus night outings (and he's willing to teach beginners, though the snorkeling is so good there's no pressing need to trade up). Shallow and calm, the waters here harbor southern stingrays, sea fans, spiny oysters, elkhorn coral, and a wrecked freighter, the Jado Trader, that functions as a fittingly decked-out fish hotel. 952/953-4124, from $1,197 per person, including meals, airport transfers, two snorkel or dive excursions (with three tanks) per day, seven-night minimum.
Palagruza Island, Croatia
Two apartments in an 1875 lighthouse on an 104-acre island. Dinner is either something you bring over on the ferry or whatever the lighthouse keeper catches that day. Each apartment sleeps four. 011-385/1-2415-611, privateislandsonline.com, $233 per week.
Trinity Island, Ireland
A three-bedroom, solar-paneled lodge on a 150-acre island that's a two-hour drive from Dublin. The island has the ruins of a 750-year-old monastery, as well as rowboats and canoes for guests to explore the interconnecting rivers and lakes of the island. Sleeps six. 011-353/49-433-4314, trinityisland.com, from $864 per weekend.
Pohuenui Island, New Zealand
The light-filled farmhouse is stunning, but even it can't compare to the countless sandy coves dotting the more than 30 miles of coastline. Tear yourself away from the beach long enough to check out the 3,500 resident sheep, the small ostrich farm, and the herd of alpacas. Sleeps eight. 011-49/40-330-000, vladi-private-islands.de, from $720 per day.
Hunt Island, Canada
Set about 80 miles outside of Halifax, Nova Scotia, the idyllic three-bedroom cabin is nestled on the wooded shores of Lake Ponhook. The island comes with a fully loaded boathouse, and the placid waters make for perfect kayaking and water-skiing conditions. Accommodations are simple and cozy: an antique wood-burning fireplace and a secluded outdoor deck. Sleeps six. 011-49/40-330-000, vladi-private-islands.de, from $278 per day, three-day minimum.