Queenslandâs lively Townsville is famous for one of the best dive sites in the World, the Yongala Wreck.
More than a century ago, the SS Yongala went down, with the loss of all hands. In sand on the bottom, some 33 metres down and in indifferent visibility (usually 10-15 metres), the site experiences quite strong currents and is reserved for experienced divers.
But those who are allowed to go there report an astonishing variety of sea creatures, from manta rays and barracuda to sharks and even, during the winter, minke or humpback whales â all against a stunning backdrop of hard and soft coral.
The Yongala is a three-hour trip from Townsville and a number of live-aboard ships take in the site as part of a cruise through the Great Barrier Reef.
Over on the west coast is the Ningaloo Reef, some 260 kilometres of fringing coral reef along the Northwest Cape. The Ningaloo is particularly famous for whale sharks, the largest fish in the world, but a variety of rare turtles, rays, humpback whales and more than 250 other species also abound here.
Christmas Island has, alas, attracted attention in recent years for things outside tourism, but the deep waters of this little volcanic outcrop in the Indian Ocean make for some amazing diving (although the monsoon from December to April is a time to avoid).
Tuna and trevally abound, but a rare sight is the annual migration of more than 100 million red crabs across the beaches to the sea to release their eggs.
As the tropical seas meet the cooler waters coming up from Antarctica, Julian Rocks in New South Walesâ Byron Bay make for interesting diving.
During the winter, itâs said, you can actually hear the migrating humpback whales singing as they pass through the area in winter, while the summer is the time to see leopard sharks frolicking. Wobbegongs inhabit the area, as well as sea turtles, manta rays and loads of colourful coral and sponges.
Lord Howe Island is hardly on the way to anywhere, but if you can make it there you are in for a treat.
The steep, wooded island has more than 50 dive sites and you can simply stroll from the beach to see the beautiful coral reef. A short boat ride to Erscotts Hole offers plenty of fish life in almost any weather conditions.
Lord Howe Island is famous for consistent, excellent visibility, making it great for underwater photography. There are plenty of bluefish, double header wrasse, spangled emperors and neon damsels, as well as rare species like Colemanâs pigmy seahorse, Fosterâs hawkfish and marlin spike auger shells.