A Reef encounter: Falling in love with Australia's natural heritage

We left the ancient rainforest of north Queensland's coast behind us, a ribbon of white sand all that separates those mountain-jungles from the turquoise depths of the Coral Sea. Our 10-seater Cessna spluttered over saltwater crocs basking on the Cairns mudflats, and, as the pilot headed north towards the tip of the Great Barrier Reef, we danced about in the hot currents.

That flight low over the water – 170 miles of dips and thrills – was the start of an adventure that would take us back to the 1700s, when Europeans first explored these shoals. Over the following fortnight I hopped from atoll to cay down the length of the Barrier Reef. It was an immersion in the pristine savagery that is Australia's natural heritage – with some good company, and tasty food and wine, thrown in. I also fell in love with diving and the world it unlocks a few feet beneath the ocean surface.

Our first destination was Lizard Island, an imposing rock rising 360 metres straight out of the water – a mountain cut off from the mainland by rising waters during the last Ice Age.

Lizard is seclusion: its population consists of four marine biologists, a few dozen hotel guests and some maids. There's no phone signal, the doors don't have locks and the evening entertainment is stargazing.

Our plane bumped to a halt on the tiny runway and we raced to our cabins to change for snorkelling. The descent over the Blue Lagoon had been exhilarating, but nothing could prepare you for the aquatic carnival up close: hundreds of fish in every direction you turned, clashing colours and patterns jostling for space in the water. The orange flash of an invasion of anthias, regiments of blue fusiliers with their brilliant yellow tails, the loud crunch of parrotfish grazing the coral shallows – this was a revelation. And then there was the terror, which still lives with me now, of paddling out across the deep lagoon, searching anxiously beneath for long shadows.

The jagged coral here trapped Lieutenant James Cook in August 1770, during his first voyage to the Pacific (shortly after he 'discovered' Australia's east coast). The labyrinth of reefs threatened to tear apart HMS Endeavour, leaving the vessel's despairing captain "altogether at a loss which way to steer". So Cook set ashore, rechristening the land Lizard Island because of the thousands of large goannas that roam the beaches and slopes, their forked tongues darting for prey. Uninventive, perhaps, but then he was having a bad day.

Cook and his botanist, Joseph Banks, hit upon the idea of climbing Lizard's summit to spot their escape route through the reef. Retracing their steps, even without wearing 18th-century naval dress, is a cracker of a bush walk, through mangrove swamp and up stone slabs in flattening humidity. But the panorama at the top is worth every metre of climbing. Lizard's peak, now known as Cook's Look, offers 360 degrees of Pacific wilderness, hinting at the peerless grandeur of the Great Barrier Reef.

That fortnight was a blur, of swimming with turtles and jetskiing in the cooler waters of the Whitsundays; anchoring off islands called Black and Hayman and Hook before plunging into their shallows to drift with Technicolor schools. On cosmopolitan Hamilton we dined well and hit the bars. Green Island, a speck of sand you can circuit in 15 minutes running, offered eco-lodge luxury and a feral charm that has drawn picnickers since the 1880s, when a party of men would typically arrive armed with "rifles, 16 jars of whisky, 20 charges of dynamite and a bottle of brandy for snakebites".

The highlight? You don't forget your first sharks. It was my debut dive, off a bobbing pontoon on the very outer edge of the Great Barrier Reef. The bucking catamaran and four-metre swell had separated the seaworthy from their bilious fellow passengers. After a brief tutorial we were sinking into the world of formless shadows and fractured sunbeams that I now find so intoxicating. Inquisitive residents of Norman Reef gathered to inspect us.

Out of the blue, 15 metres away, the gloom consolidated and assumed a familiar silhouette. Shark. Looks large. We huddled together, hearts drumming, taking sanctuary near the bottom as she turned on a pin and headed slowly for us. Sliding into visibility behind her, another grey reef shark – a curious predator, but pretty harmless during daytime. Time froze as they circled back and forth. And as suddenly as they appeared, they slipped back into the Pacific's unseen expanse.

If you must leave paradise, you may as well leave it in style. The flight off the Reef was our pilot's last before he left the bush airline for a life in the cockpit of long-haul jumbos. After a steep take-off, he turned to look at us with a big grin on his face. He dropped his left wing and flew sideways round the island. Then, whooping, he flew round it again.

Island hopping

* Visitors to the Channel Islands tend to stick to one destination but it's perfectly possible to hop across the archipelago's five main isles. The Channel Islands Way is a guide detailing a 110-mile walking route along the dramatic coastlines and distinct cultures of these islands. perrysci.com

* Being touted as Thailand 50 years ago, the 60-odd islands of Cambodia's south coast are near-pristine. Accommodation is of the stilted-hut kind and travel is by tiny boats from the coastal towns of Kep, Koh Kong and Sihanoukville, but with new flights linking the latter to the Angkor temple hub town of Siem Reap, this is a destination on the up. aboutasiatravel.com

* Closer to Taiwan than Tokyo, the Okinawa islands in Japan's far south are one of the country's last frontiers, a bastion of rural Ryukyu culture. This chain of some 160 islands is a subtropical paradise for sea kayakers, trekkers, snorkellers and lovers of hot springs. insidejapantours.com