Some islands can be bought undeveloped, while others already have roads and/or houses. Islands are also available for rent. Many celebrities have their own private islands. Commercial development of uninhabited islands can raise ecological concerns, as many have a fragile environment.

Believe it or not, there are several websites dedicated solely to finding the perfect private island to purchase. You can find private islands for sale via Private Islands Inc. or Vladi Private Islands, or by contacting a realtor who specializes in big-ticket sales.

The main difference between an agent and broker is the number of responsibilities they're able to take on. A broker can do everything an agent can do, but they have the added responsibility of making sure all real estate transactions are lawful, all paperwork is accurately completed and all finances are accounted for.

More than two years passed before he could get another commission but by then Krolow had 80 islands for sale, in different parts of the world. He also started buying islands himself. He and his company now own more than a dozen islands — in Canada, Panama, Belize and Fiji — which are rented out as holiday lets.