Western Australia (here's the map) is Australia's largest state in area, covering the western third of the mainland, and is bordered by South Australia and the Northern Territory. Its capital Perth is closer to Singapore and Jakarta than it is to Canberra. The majority of people live in and around Perth.  Perth boasts more sunny days per year than any other Australian capital city so sunshine is usually the standard order.

With thousands of kilometres of coastline, hundreds of nearby islands, abundant and varied marine life, a mix of tropical and temperate climates and numerous shipwrecks just offshore, the quality of the diving in Western Australia is every bit as good at the Great Barrier Reef, but without the crowds, and is often overlooked.

The main diving area are:

Rottnest Island, just off the coast of the capital city Perth. With a Mediterranean climate, miles of white sandy beach, crystal clear waters, 13 historical wrecks, 360 species of fish and 20 species of coral, Rottnest Island is a true diver's delight.  The island is the southernmost point along the Western Australian coastline at which coral grows.  The Rottnest shipwreck trail tells stories of the 14 shipwrecks found along its coast and information plaques can be seen on the ocean bed.

Ningaloo Reef and Exmouth have become famous in the diving world for the large numbers of Whale Sharks that visit each year from April to June. 

An hour south of Perth, you'll find Shoalwater Marine Park, home to seals and penguins.

Further south at Dunsborough, there's the destroyer escort HMAS Swan and HMAS Perth can be found 409 kilometers from Perth off the coast of Albany.

And, for non divers, there's the Busselton Jetty Underwater Observatory which allows you to descend eight metres below sea level to view an amazing marine world of schooling fish and tropical coral.

• A spotter plane communicates with boats as it spots whale sharks near the surface. Interactions are regulated by CALM (Conservation and Land Management), which limits the number of snorkellers in the water with a shark to a maximum of 10, forbids the use of flash photography and lists guidelines including how long a single interaction with a whale shark may last.
• In spite of their size, whale sharks are fairly docile; the main risk to humans comes from getting in the way of their powerful tails.
• In Australia, you must have a Recreational scuba diving medical to Australian Standard 4005.1 2000 (AS4005.1 2000).  The South Pacific Underwater Medicine Society lists doctors who have completed a Diving Medical Course and will be able to perform these Medicals. Medicals incur a fee which you pay directly to the doctor.