Someone bought a private island in the Florida Keys for $11 million The sale is the highest of several recent Florida Keys private islands. Â Â An aerial view shows a private island off the Florida Keys that sold in March 2021 for $11 million. [ Ocean Sotheby's ] By David Goodhue, Miami Herald Published Mar. 12 Updated Mar. 12 A private island sold in the Florida Keys this month for $11 million, one of the highest closing costs for an island sale in the archipelago. The transaction is a monument to a trend this year of high-end buyers coming to the Keys from other states looking to own a piece of paradise, local real estate agents say.