“Your mission, should you choose to accept it,” crackles the voice over my phone, “is to not leave town until you are battered, bruised and more than a little hungover. Got it?”

“No problem,” I think. After all, those activities happen to be my three specialties.

It’s then that my Mission Beach chaperone, as if on cue, appears before me, with a grin on his face and an eye on the brilliant blue sky. “Right then,” he says, “we better get you up there”.

It’s the first of my four days in Mission Beach, which at first glance had seemed more than enough to do justice to this seemingly-sleepy town just south of Cairns.

Indeed, thanks to being surrounded by highly-protected World Heritage-listed rainforests, big developments have failed to get a footing in the area, meaning that Mission Beach, actually a string of several beaches spread over 14km, has succeeded in keeping its small town feel.

But to think there’s nothing going on is a huge schoolboy error. Lurking beyond the spectacular stretches of sand, cocktails and hammocks are some of Australia’s most exciting activities.

Approaching from all sides but one is the jungle. Some experts claim it’s home to even more forms of life than the average dorm bed, but it’s the giant and very odd-looking cassowary which is the real star of the show. Nowhere else in the world are you more likely to spot one of these huge birds in the wild.

Beyond the trees lies the equally wild Tully River, arguably the best place to go whitewater rafting in Australia. Meanwhile, almost touching the trees is the ocean, from where you’re just a few splashes away from the Great Barrier Reef.

And if that wasn’t enough, overlooking the reef are islands so drop-dead gorgeous that they boast a $3,000 a night resort, fancy enough to regularly host the likes of Jessica Alba, Justin Timberlake and even Fergie (as in the ex-princess, not the pea).

In other words, I have a lot to do, meaning stalking Jessica is just going to have to wait (again, sigh).

Chute up

My first appointment is with another activity that this corner of Tropical North Queensland has rightly become very famous for – skydiving.

I’ve skydived once before, meaning that as I pull on my jumpsuit, I feel calm. Cocky almost. After all, I know what to expect and can well remember how much I’d loved it the first time.

But stepping onto the tiny plane, everything changes. The terror takes hold as we head slowly and shakily up to 14,000ft. Below us we can see the Tully River, an endless line of beach and the sparkling ocean, dotted with the Family Islands and the Great Barrier Reef itself.

I still find it hard to control The Fear in these situations. I know it’s perfectly safe (well, sort of). And that I’m going to love it. But for some reason, however, my bastard brain insists on turning me into a demented wreck whenever I’m about to jump into thin air.

Anyway, with The Fear just about under control, the door flings open. The deafening whoosh means just one thing… My time has come.

Edging over to the gaping hole, my legs dangle through and I look down. Even second time around, I’m in complete disbelief as I watch the world rush past between my legs.

Suddenly we’re gone and it’s rush hour. I woop and yell, scream and grin like a man in a padded cell. It’s even better than I remember.

This time I have another skydiver jumping with me as a cameraman. He flies in and out, we play around pretending to swim through the air, or grabbing hands, while we drop towards the ground like stones. It’s brilliant fun and, not being quite so overwhelmed by the experience second time around, I take in just how stunning the view is as I plummet Earth-bound. It’s as good as any scenic flight I’ve ever taken, except this time I’m the aeroplane.

Then the chute opens and my instructor turns viciously to the left and right, spinning us down towards the beach like the most evil rollercoaster imaginable as we suddenly dip towards the beach and feel sand beneath other feet.

I’m back on solid ground, wandering if I’ll still be scared the third time. No doubt my stomach will… it lasts half an hour before I throw up on the street.

No rest for the wicked though as I’m slung straight on a boat. With other backpackers on board and the beers now flowing freely, we zig zag our way along rivers, trying to spot crocodiles in the thick jungle that encroaches from either side.

Soon we’re out on the open sea and darting from one island to the next, pulling up at deserted beaches to snorkel and munch food before skimming back to town (and the bar), mesmerised by a spectacular sunset.

Good reef

Next morning I’m up early. Shaking an alcoholic haze from my head, I’m straight back on the water, eager to keep my meeting with the Great Barrier Reef.

The ocean, my stomach is very relieved to see, is as flat as a pancake, like a blue carpet stretched out before us. We make it to Eddy Reef an hour or two later, having barely seen another boat. We waste no time in getting tanked up and heading straight down to the underwater world.

Forget sticking on some funny glasses and watching strangely-sexy blue people running around in Avatardiving really is like entering another world. It amazes me every time.

Surrounded by warm waters we float across the reef. Shoals of multi-coloured fish cruise past, while after just 10 metres we come across two turtles chilling on the sandy floor.

They give us some disdainful looks for a minute or so before flapping off to find somewhere more private. On we go, stopping to pick up a sea cucumber and experiment with making giant clams close. It’s nothing short of incredible the amount of life on display whichever way we look, thanks in large part to there being far fewer tourists on the reef here.

We head back to dry land through the glorious sunshine, admiring the rainforest-clad islands that dot the horizon, surrounded by their beach halos.

Day three and I rise early again. The hangover is worse this time, as I desperately try to piece together fragmented memories of the previous night. A bar called the Shrubbery perhaps. Or maybe I’d just been dreaming of Monty Python’s Holy Grail

My stomach is in for another test as I jump on a bus and start winding through the rainforest. Luckily, it’s not too long to my destination – the Tully River, the location for my next challenge, whitewater rafting.

Rapid descent

I’ve never rafted before so I’m excited. Even more so when I’m handed a wristband for one of the “Xtreme” rafts.

It very quickly becomes clear that a key part of “Xtreme” rafting is not spending much time in the boat.

Sure enough, with our guide Sam screaming instructions, we paddle like fury, cling on and feel the rush. Speeding through the Grade 4 rapids and bouncing off the rocks is exhilarating and quickly becomes addictive.

While at first we’re sceptical of Sam tipping us all into the water, tumbling over with limbs and paddles everywhere, we’re soon urging him to do it again. And again. This is seriously good fun.

Later on we dispense with the raft altogether and give swimming through the rapids a go, at times having no control as we’re sucked under, just having to hold our breath and hope, with no idea which way is up or down, waiting for the water to decide when it wants to spit us back out. 

Staggering out of the water five hours later – battered, bruised, sunburnt and bleeding – I knew my mission was safe. 

But it’s not over yet. On my final morning I jump aboard Sealegs, a crazy amphibious speedboat that drives up onto the beach, James Bond-style, to pick me up and take me over to Dunk Island.

Just 4km offshore, Dunk Island is not just a national park-dominated tropical island, but also a place with a serious passion for water sports. Meaning I couldn’t leave town without checking it out.

I’m straight onto a jetski for some high-powered talks. In between speeding across the surf at breakneck speeds and scanning the crystal clear waters for sharks and rays, we pull into secluded bays to hear about the Aboriginal legends and gold-digging myths that abound on the rainforest-clad island. It’s thrilling to skim across the water, and brilliant to actually be in control for once. My hour-and-a-half flies by, however, and I’m soon back in Mission Beach.

Limping out of town, very battered, very bruised and very hungover, I confidently put in the call. “Mission accomplished.”

The damage & the details: Jump from 14,000ft with Skydive Mission Beach (Ph: 1800 800 840, www.skydivemissionbeach.com) from $299; Full day Xtreme whitewater rafting with Raging Thunder (Ph: 07 4030 7990, www.ragingthunder.com.au) costs from $215; Full day reef trip including two dives with Calypso Dive (ph: 07 4068 8432, www.calypsoadventures.com.au) costs from $250. Calypso also run the jetski tours ($230) and Sealegs amphibian boat ($22 each way). Sunset boat trips organised by Mission Beach Water Taxi (Ph: 07 4068 8310,www.missionbeachwatertaxi.com); Beds at Absolute Backpackers (Ph: 1800 688 316,www.absolutebackpackers.com.au) cost from $23 a night; Beds at Scotty’s (Ph: 1800 665 567,www.scottysbeachhouse.com.au) cost from $24 a night.