The Flower Gardens National Marine Sanctuary is a premier diving destination about 100 miles off the coast of Freeport. This is where the northernmost coral reefs in the continental United States are located. If you want to see Star and Brain coral, Manta Rays, Hammerhead sharks, and Loggerhead sea turtles then book a trip with the local dive charter. You might even spot a whale shark if you visit this national treasure in July, August or September. Best suited for intermediate or advanced divers. Contact Texas Caribbean Charters, 979-233-4445.