Snorkel or dive in some of the most pristine marine ecosystems in the world. Discover coral gardens teeming with tropical fish, waters harboring sea lions or whale sharks, brilliant blue holes, and much more. A number of our small-ship voyages are equipped for scuba diving—in waters as rich as the Belize Barrier Reef and the far-flung atolls of Polynesia. Delve into vibrant undersea realms while snorkeling or diving (at additional cost) on the voyages below.