Do yourself the favor of hopping a ferry to Rottnest Island, one of the best places to swim, snorkel, and dive on the western coast of Australia. The tropical/temperate climate ensures for an amazingly diverse biosphere, while a number of excellent dive and snorkel sites make enjoying the sea life an easy affair. There is a shipwreck trail, which includes over a dozen labeled underwater wrecks that surround the island, part of a 'museum-without-walls' concept that has become popular since its inception. Kingston Reef, Parker Point, and Fish Hook Bay are some quality diving and snorkeling destinations. Consult the included site for more information.