There are two national parks in St. Augustine - the Castillo de San Marcos and Fort Matanzas. The Castillo is definitely a "must see" as it is conveniently located in the Historic area of St. Augustine. Fort Matanzas is located approximately 15 minutes south of St. Augustine and is a much smaller fort accessible only by boat (free ride) to the site, but definitely of interest to those that love history and a free boat ride!
Blackbeard’s Treasure Hunt is one of several special voyages offered by the Black Raven Pirate Ship, and it allows guests to watch as the sailors engage in a sea battle with Queen Anne’s Revenge, another ship. There are sword fights and cannon fire, things that the whole family will enjoy. Kid's love this 2-hour voyage on the bay.