St. Nicholas III and VII are historic sponge diving boats in Tarpon Springs, Florida. They are located at the World Famous Tarpon Springs Sponge Docks at Dodecanese Boulevard. On August 3, 1990, they were added to the U.S. National Register of Historic Places. St. Nicholas Boat Lines will take you on a half hour tour down the Anclote River as the Captain gives a lecture on the history of sponge diving. A diver in a traditional suit will demonstrate how sponge are retrieved and prepared for marketing. Since 1924 St. Nicholas Boat Lines has welcomed tourists from all over the world and is a favorite educational field trip for students from Pre-school through college..