Military service members and their dependents can get into SeaWorld and Busch Gardens for free once a year. It's for the service member and up to 3 dependents, If the dependants are over a certain age then their Military ID is required in order to use the ticket. When we went this year, My husband and I had to show our Military IDs.
You can only use this once per calendar year for one park. On January 1st your able to use it again, even if you used it on December 31st because January 1st starts the new calendar year.