A large continent means big drives, and my first port of call involved a six-hour journey from Adelaide to the unobtrusive town of Whyalla.
Each year between May and August thousands of giant Australian cuttlefish (Sepia apama) descend on this sleepy coastline to breed.
Its probably the only place in the world where you are guaranteed a ringside seat. And its worth every minute of the long journey and chilly 12°C temperature.
There are a few locations around the bay where the cuttlefish migrate en masse, but my guide Carey Harmer assures me that Black Point is the best.
We arrive early, and the shallow water is flat, calm and relatively clear. Apparently this is very unusual, and Carey is excited that we have the perfect weather for observing our cephalopod stars.
Its a short walk down a wooden staircase and a stagger across small jagged rocks to the waters edge. Most of the dive will be spent at around 4m, and within 30 seconds of snorkelling out to this depth I spot my first cuttlefish lazily hanging out next to a rock.
Shes protecting her string of eggs, just visible under the rock ledge. There is no sign of her mate. Sadly, the cuttlefish motto is live fast and die young. Both males and females reproduce only once, and die soon afterwards.
We glide over a terrain of beige algae clinging to a sandy bottom. The sea floor looks to be coated with cotton wool, like natures way of laying out a bed for these highly sexed creatures.
Then I notice a whitish-purple colour pulsating from within the strands, and realise that at least 30 cuttlefish are congregated around me. Wow!
Some of these guys are huge. The giant Australian cuttlefish is the largest of the 100 or so cuttlefish species and can grow up to 1.5m long and weigh up to 15kg.
The largest in this group measures about 1m, and theyre not afraid of putting on a show. No wonder theyre often dubbed chameleons of the sea.
They are so unbothered by me and my camera that I park myself within inches of five males trying to impress a lone female. I can only describe the spectacle as a kaleidoscopic colour-off, as the cuttlefish use an intricate combination of colour and body language to fight with the other males.
After a few minutes the one with the most intense blasts of colour emerges as the champion. But all is not as it seems in the world of mating cuttlefish. Remember, these cephalopods are very intelligent and, it seems, quite devious.
Just as the winner is getting down to it with his prize female, another cuttlefish joins in on the action.
To my amazement, I witness what Carey describes as sneaky sex. The smaller male who cant compete with the larger one changes his body colour and pretends hes a girl.
When the larger male isnt looking, he quickly changes back, and mates with the female right under his nose!
You cant help but admire this devious, intelligent, mesmerising and beautiful creature, and at Whyalla you can witness this underwater spectacle at close quarters.

The next dive stop is just 90 minutes scenic drive south of Adelaide along the Fleurieu Peninsula. Avoid the lure of the wineries en route and head to Marina St Vincent at Yankalilla Bay, the meeting point for a short boat ride to South Australias most famous wreck, the ex-HMAS Hobart.
This wreck, unlike most of the other 700 along South Australias coastline, is fully intact. Scuttled in 2002 as an artificial reef and marine reserve, it was one of three Charles F Adams-class guided missile destroyers built for the Royal Australian Navy.
Its sister-ships are also artificial reefs (HMAS Perth in Albany, Western Australia and HMAS Brisbane off Mooloolaba, Queensland).
Divers can explore the smokestacks, engine-rooms, missile-launchers and gun turrets, though not all on the same dive. Hobart stretches 133m along the seabed, and divers can access 90,000sq m of it. I couldnt wait.
Again we are blessed with a perfect calm day. The top of the front stack is visible 5m below the surface. Our skipper expertly drops us in on a slack tide to avoid the currents famous for hurtling through the ship.
Descending the guideline, we pass the conning tower/front stack and radar, and shimmy down the side of the starboard hull to land on the seabed in around 30m.
Even with such 15m-plus visibility its difficult to perceive this vast ship as a whole. Five years on, much of its hull is encrusted with soft and hard corals, and several schools of snapper swirl around us as we head for the sonar dome.
After a few moments gazing up at the bow, we ascend on the port side to the mess/kitchen and dining-room areas, where we penetrate the wreck for the first time.
We swim over a dinner setting - tables and chairs stacked up as if we had been expected. The main course seems to be a lionfish, idly cruising the table-legs.
A school of snapper hang just outside the man-made exit, and we follow them back into the deep blue.
Next we swim onto the forecastle deck, in search of the front gun at 15m. Bearded cod roam around us, and leatherjackets munch on its base, oblivious to the power that this gun once exerted.
Finally we make our way to what will be my favourite part of the dive, the bridge. Torches are shining through whats left of its windows, creating a slightly eerie perspective. Ours soon join them, and we spend a few minutes checking out the captains chair, where assortments of pink and yellow anemones have set up camp.
How many important military decisions were made from this once-leather pillar of power We couldnt wonder for long. It was time to ascend back up the conning tower/front stack and radar.
Hanging by the crows nest and looking back down across the deck, I felt a little frustrated that I had only really touched the surface of this piece of Australian history. Had we really been down here for 45 minutes
We missed many of the smaller fixtures and fittings such as the filing cabinets, sinks, toilets and even the infamous ironing board in the laundry. Not to mention the engine-room and missile magazines. One dive isnt enough to appreciate the Hobart, so aim for a couple.

Just around the corner and three miles south is, arguably, one of Australias best jetty dives. Its also one of only a few spots in the world where you can see the elusive leafy sea dragon. Ive been itching to photograph this charismatic creature, so my hopes are high as I jump into the shallow 10m waters.
The jetty is obviously at its best when the sun is shining. Streams of light penetrate the holes in the planking, chasing us as we descend. Its almost like runway lights steering you down.
Moving through the pylons is like drifting through a huge Canadian forest. As you navigate around the long, thin silhouetted trunks, its as if leafy branches are sprouting just above the surface. As we cruise along the 470m jetty, I am impressed by the thick seagrass. Its everywhere.
The seagrass beds camouflage a multitude of life, including floating anemones, tubeworms and gigantic sea-squirts. A patch of what look like white flower buds waft in the light surge.
This is definitely leafy sea dragon territory, and theres also a good chance of spotting its slightly more common cousin, the weedy sea dragon.
After quite a few patient minutes we find our first leafy. Luckily were with an expert spotter, because its so well-camouflaged that I almost run over it with my camera.
Its a beautiful creature, so delicate and shy. Its long tubular snout moves towards me, almost in a nod.
Of course, as soon as I try to take a photograph, it turns its head away coyly. After plenty of time for observation (leafies are slow movers) we continue towards the 200m-long T-section, where most of the life hides out.
A large school of old wives has taken up residence, and a school of kingfish dip in and out of the pylons on the hunt.
We spot tiny gobies, magpie perch, goatfish and wrasse, as well as globefish, soldierfish and an inquisitive octopus peering out from the seagrass.
Sand and anemone crabs live in the nooks and crannies, and they share them with a multicoloured fiesta of sponges. From Aplysian to Aconthella kelthra, this is sponge-nerd heaven! Ive never seen such a collection - yellows, oranges, pinks and reds, the colours so vibrant you wont need any Photoshop assistance after this dive.
Also, for those with time to look (and at 10m you should have plenty) there are rarer finds such as blue-ringed octopus and spectacular nudibranchs.
The jetty is well-protected from the ocean swell by a small headland, so its an easy dive, and even a great snorkel.
It also regularly sees 15-20m vis at slack tide.
Sea-lions and New Zealand fur seals are often seen in the area too, as are southern right whales and occasionally pilot whales and pygmy sperm whales during winter.
I booked a double boat dive to explore the Hobart and Rapid Bay Jetty (the easiest way), but I enjoyed the jetty so much that I stayed an extra day to dive it again! Accessing the jetty from the shore does involve clambering over quite a few large slippery rocks and a long surface swim, but Kerry at Aussieextreme can arrange dive gear, accommodation, airport pick-ups and even a dive buddy!

Ewen Ponds is situated in the Mount Gambier region of SA, famous for its cave-diving. Ewens is a series of three ponds linked by shallow channels. These sinkholes make up a part of a lake system formed by volcanic activity.
You can fly into Mount Gambier from Adelaide and then drive half an hour to Port MacDonnell, or take a leisurely drive down the coast through the Coorong National Park and clock up another 295 in car miles.
When you eventually arrive at Ewen Ponds, it looks like any farm pond in the UK - ducks quack about on the surface and corn strands waft in the breeze.
But under the surface stillness is a secret world thats been in the making for centuries.
You enter the first and largest pond from a wooden boardwalk, hovering over a shallow outcrop.
Red algae strands loom up from the bottom just a few metres down, but its only when you descend over the ledge into the pond itself that you feel as if youve entered another world.
In fact, imagine diving Stoney Cove with 80m-plus vis. Ewen Ponds offers this experience, minus a few hundred students and frisky freshwater pike!
Peering into the 10m-deep basin is like looking into a meteorite crater.
Its almost alien. The bottom is a combination of large rock clusters covered in purple algae and uneven patches of sand smothered with thick black silt. Its not a dive on which to check your buoyancy - one outlandish move, and youre engulfed in a grey cloud for quite some time.
Forewarned, I hover over the bottom at a safe distance while searching for life. Just like Mars, however, Ewen seems to be lacking in this department.
Instead, I notice the sand bubbling up from underneath - the secret of the ponds clarity.
The ponds are fed by underwater springs, and over thousands of years limestone has filtered this water. Its so clear that some plant species are found growing fully submerged under water, as deep as 6m. Theyre among the deepest freshwater plants in the world, and some species are found only here.
But where are the fish Im about to give up when something catches my eye and a freshwater crayfish, or pricklyback, emerges from a hole in the rock and meanders along the bottom. Apparently theyre a common sight here.
Something else moves. Its John, my guide, gesturing me to ascend as the second pond beckons. The channels that link them are very shallow, and can be navigated only while snorkelling. Floating through them is a tight squeeze.
The current (where does that come from) drags you along, and youre swallowed up by aquatic reeds. Its so thick that all you can see is green and dashes of sparkling light as the sun penetrates the crystal-clear water. Suddenly a blue hole looms in the distance, and before you know it youve been spat out into pond two.
The terrain here is totally different, resembling an expansive green grassy meadow. I can see signs of life, too - a small school of perch about 30m away, ambling through the shorter patches.
After a short look around, theres another roller-coaster dash through the next, even-denser channel, which takes you to the third and final pond.
This one is different again. The plant life is prolific, but there are also some rocky patches. Theres even an overhang to explore, obviously the best hiding-place for the locals. We uncover a party of bream and a freshwater eel in the safety of the caves shadows.
And then comes the worst part of the dive - the end. Diving Ewen Ponds is an other-worldly experience. Imagine swimming about on a far-off planet, and youre a little closer to what its like to dive into these big bowls of clarity.


Just a short drive from Ewen is the world-famous cave site Piccaninnie Ponds (Pics for short) in Port MacDonnell National Park. This is our afternoon adventure, but unfortunately you cant dive here unless youre properly accredited (holding at least a cavern sinkhole diver certification).
However, its worth a snorkel any day of the year.
Like Ewen, Pics is unimpressive from the surface, although it does appear to have more life living in and around its banks. As we gear up, a black swan stretches its wings and a heron skims the surface.
Snorkelling Pics is quite unlike diving Ewen Ponds. The plant life is much denser around the edges, and much of it is pretty shallow, so its easy to immerse yourself within the multicoloured reeds.
Its a bit like swimming through a giant underwater forest tinged with a blue halo.
The crystal waters have been slowly filtering through the limestone for thousands of years, the pressure of fresh water rising to the surface eroding its walls to form a vertical chasm 37m deep and 5m wide. You seem to be teetering on the edge of the abyss.
Sprouting off from the Chasm is the Cathedral, with its spectacular white limestone walls. The clarity of the water makes this one of the most spectacular and accessible cave-dives in Australia.
To protect this fragile ecosystem, permits to dive or snorkel the pond are required and are limited, so book well in advance. Any time is a good time to explore both ponds, although winter (June to September) is usually the clearest.

You cant come all the way to South Australia and not go in search of the great white. Its only when you come face to face with this shark that you can truly appreciate its power.
The trip is fantastic, which is handy because there are no guarantees that you will even see a shark. To ensure that you get your moneys worth Andrew Fox (Rodney Foxs son, who now runs the show) packs the three-day liveaboard with yummy food, a great crew and free wine and beer after the dive day.
You also get the chance to snorkel with Australian sea-lions and get up close with seal pups on Neptune Island. The presence of so many sea mammals supports the large population of sharks.
Having arrived at North Neptune Islands, about 50 miles from Port Lincoln, Andrew Fox gets stuck into the bait and we play the waiting game. We have no luck on the first afternoon, but the second day brings two shark fins lurking off the stern.
Some divers have travelled from the USA and Europe, and a wave of excitement flows through the back deck as we gear up. Everyone is anxious to jump into the surface cage to observe the sharks up close. I live only a few hours by plane from Port Lincoln and cant believe I havent done this before -- the adrenalin rush is electric.
As you bob around in the surface cage, your senses are heightened. Every glint of grey requires attention, and all eyes are peeled on the bait.
Suddenly a diver screams and points to his left - and our first white shark encounter has begun. To see a 4m shark loom up from the depths is humbling. They are certainly curious creatures and spend some of the dive checking us out rather than trying to snag the bait.
Watching a great white rip into a large piece of tuna is pretty cool, though I preferred the bottom cage-diving, where you see the sharks in their natural habitat.
When I entered the cage, suspended 5m above the surface by a chain that looked as if it had seen some salt water in its time, and saw that giant grey shadow circling below me, I was nervous.
Once you start the descent, movement is restricted, especially if you have a large camera set-up. Heads jerk around furiously. But we didnt need to worry; the sharks search us out, cruising in as soon as we near the bottom.
Observing these guys at depth is a different experience. Yes, we have two big tuna and some burley in the cage, but they seem more curious about us than anything else. In fact, Im surprised by how little aggression they display.
At depth, staring into his eyes, you appreciate the power of the white pointer. The shark knows his strength - he knows you rule the surface, but down here, he is master.
Peering out from your little four by four iron prison, you can afford to be smug, but it also crosses your mind that the space between the bars is pretty wide. Perhaps its time to move back a bit, and show him the respect he deserves.
A little later, one of the larger sharks bumps the top of the cage and shows its teeth - a reminder that it is the divers who are really on show here.
I do a lot of diving in Australia, but the chances of me seeing one of these beautiful sharks in the wild is almost zero, despite the media hype surrounding shark attacks.
For many divers this is the ultimate adrenalin thrill - at least, thats how it starts out. But by the end of the trip the guests are oozing respect for these ancient relics. Your emotions are heightened and your appreciation broadened. If you like adrenalin, adventure and big fish, you cant beat a trip to the Neptune Islands.
After a travel quota of more than 800 air miles, 1000 car miles and 110 nautical miles, that pretty much wraps up our tour. I love the Great Barrier Reef, but I dont think it offers as much variety as South Australia. Superb!

GETTING THERE: Fly to Adelaide and hire a car there - buses are too infrequent for this tour. Rapid Bay Jetty or HMAS Hobart can be dived as a day trip from Adelaide (or overnight for both).
DIVING: Whyalla Diving Adventures, www.whyalladivingadventures.com; HMAS Hobart, Underwater Sports Diving Centre, www.underwatersports.com.au; Rapid Bay Jetty, Aussiextreme, www.aussiextreme.com.au; Piccaninnie and Ewen Ponds, Port MacDonnell Dive Academy, portmacdivers@bigpond.com, permits: www.parks.sa.gov.au; Rodney Fox Shark Experience, www.rodneyfox.com.au
ACCOMMODATION: Motels, small hotels and cabins are quite reasonably priced.
WHEN TO GO: Best time for attractions such as mating cuttlefish, great white sharks and clearer water, May to July
PRICES: Flights from the UK to Adelaide, around £500. Flights on to Port Lincoln (Rodney Fox) £93 return plus taxi to boat £12. You can hire a small car in Adelaide for as little as £80 a week. Expect to pay £35-£50 per double room per night in motels, small hotels or caravan parks. For Rapid Bay Aussie Extreme can collect and return you from Adelaide for around £155 with two dives, or £125 if it picks you up from Normanville, the nearest town. Whyalla Diving Services charges around £14 for a two-tank shore dive, add £16 for a boat dive. Underwater Sports Diving Centre charges around £46 for two boat dives on HMAS Hobart. A guided tour of Ewen Ponds is also £46.
FURTHER INFORMATION: www.satourism.gov.au, www.underwater.com.au/directory.php/location/south_australia