Castaway Cay is so relaxing. Part of that comes from splitting the island up into sections, thereby allowing adults to be alone. There are numerous activities available for a fee, but the beauty of the island can best be enjoyed by simply floating in the water or basking in the sun with a cool tropical drink close at hand. Castaway Cay is located in the Bahamas and has a post office on the island but it only accepts cash. You can have your letters and postcards sent with the Bahamian postmark so be sure to take along a list of addresses.