You can only use the island for a specific time - meaning that the longer you own the island, the less the developments, for which you have paid, are worth. If the lease is for a specific use and you wish to change the use, you may lose your rights to the island.

There are tens of thousands of private islands in the world, ranging from a few dozen square feet to hundreds of square miles. Usually, they are governed by the laws of a nearby country but restricted to use by the owner alone.