I am a Civil Registrar of Marriages in the Cayman Islands. Your Cayman Islands marriage is legal worldwide, and you don't have to register it in your home state. You DO have to get a Registered Marriage Certificate from the Cayman Islands Government (Registrar of Marriages) after your wedding has been performed, and your Marriage Officer has filed it. Usually your Marriage Officer will mail this to you a couple of days after the wedding. Make sure this is part of your package, as this is your official marriage certificate and you will need it to change your Driver's License, Social Security, bank accounts etc. Have a lovely day in the beautiful Cayman Islands, May is a lovely time to be married.