I have ridden on the beach at Cocoa Beach for may years. Just ride at low tide on the hard packed sand and never go in the water. Last ride on the beach at low tide was from Patrick AFB to Port Canaveral. I always wash off my bike after riding on the beach. And always check the tides. I live about 6 miles from the Atlantic Ocean and about 10 miles from Port Canaveral.
Enjoy
Em