While Australia is a wonderful country for finding your own piece of heaven, there are some places that even the hardiest adventurer just is going to be able to get to. Whether off limits for wildlife protection, military manoeuvres or sheer inaccessibility, we've picked out 10 parts of Oz you're just not going to get – as well as 10 much more agreeable alternatives.

Pine Gap

While it's hardly a top secret base, there's a remarkable reticence to state exactly what goes on at the Pine Gap Joint Defence Facility.

Located 18km south-west of Alice Springs, it doesn't come as too much of a surprise to learn that this Australian-American military base is used as a satellite tracking station. The large antennas pointing at the heavens give that away. But information on any other intelligence activities conducted at Pine Gap is kept deliberately hidden.

Unless you work there, you're not getting in. Road signs nearby are very clear about this. And don't think about a scenic flight overhead either – there's a no fly zone.

Accessible alternative: The communication with satellites is considerably less cloak and dagger at the NASA-funded Canberra Deep Space Communication Complex. The visitor centre goes into Australia's role in space exploration, and the field of giant radio telescopes outside make for impressive eye candy.

Heard Island

Effectively a big volcano in the middle of nowhere – it's about 1000km north of Antarctica, and more than 4000km from both South Africa and the Australian mainland – Heard Island is an Australian external territory.

At 2750m, Mawson Peak is the highest Australian mountain – and it's highly active. The most recent eruption was in April 2013.

If you really, really want to go there to see the penguins, glaciers, seabirds and lava flows, it's a complex process. First, you need permission from the Australian Antarctic Division (www.antarctica.gov.au). Then you need to persuade the crew of a properly kitted-out expedition boat to sail for up to two weeks across some of the roughest seas on earth. Let's just say it's unlikely.

Accessible alternative: If it's an island with an active volcano you want, hop over the ditch to White Island  in New Zealand. For penguins, try Montague Island off the coast of Narooma in New South Wales.

The Ranger Retention Pond

An absolute shoo-in for the title of Australia's least appealing swim, this large billabong on the cusp of Kakadu National Park is one you can't dip a toe into anyway. That's probably a good thing – even though the local wildlife seems to be treating it as an idyllic wetland refuge.

To protect from possible contamination, by law, all water that falls on the Ranger Uranium Mine site has to be kept there. And during the wet season, that's a hell of a lot of water.

It's not just potential radiation that's the issue, however – traps by the side of the pond indicate that saltwater crocodiles have taken up residence in there. Prime snorkelling territory it is not.

Accessible alternative: For a safe swim within Kakadu, head to the top of Gunlom Falls – the natural infinity pool there is too high up for the crocs to get at.

Heart Reef

In a piece of beautiful irony, the star of about 7,283,030 tourism marketing campaigns is one of the places in Australia no one can actually get to. Heart Reef in the Whitsundays – that island from all the promotional films that looks like a heart from above – has protected status. That means you can't land a helicopter on it, sail up to it or snorkel by it.

Of course, this would be largely pointless anyway – it doesn't look so romantic from ground level. Air Whitsunday (www.airwhitsunday.com.au) operates a range of scenic flight that give a bird's eye (and brochure photographer's) view of Heart Reef.

Accessible alternative: Multiday sailing adventures tend to go beyond the most crowded of 74 islands in the Whitsundays group. For a romantic proposal without the daytripper herds, try Shaw Island – it has brilliant beaches and walking tracks, but tends to get left off shorter itineraries due to its distance from Airlie Beach.

South Coast, Point Nepean National Park

Point Nepean – the tip of the Mornington Peninsula that hugs the eastern side of Port Philip Bay – hasn't always been a national park. Visitors are still restricted from entering large swathes of the area, and those parts tend to coincide with the parts that were used as a military firing range for many years. There's a twin reason for keeping these large patches fenced off – one is conservation, and the other is unexploded ordnance. Go walking where you shouldn't and there's an unnervingly high chance of losing a limb or two.

Boat access along the south coast of this area is prohibited for safety reasons too – rough seas and high cliffs make it too dangerous to land anywhere.

Accessible alternative: Not all of the national park is off limits. The old military forts and tunnels are open for exploration, as is the former quarantine station. It's also possible to visit Cheviot Beach, where former PM Harold Holt went missing in 1967.

Carnac Island

It's just off the coast of Fremantle, but going beyond the beach of Carnac Island requires special permission from the Department of Conservation and Land Management. Anyone arriving by boat and thinking of sneaking inland while no one's looking could be in for a very nasty surprise, however. The island is teeming with tiger snakes. For researchers in highly protective clothing, this is handy for collecting venom for medical research. For an errant daytripper sauntering along in thongs, well, er … good luck.

Accessible alternative: Regular ferries run to nearby Penguin Island from Rockingham. The wildlife here – sea lions, penguins and pelicans – is considerably less life-threatening.

Cartier Island

Lying closer to Indonesia than Australia, where the Indian Ocean meets the Timor Sea, Cartier Island is a 0.4 hectare sand cay sticking out from a reef.

It's lumped in with the also uninhabited Ashmore Islands 70km away and administered by the Department of Transport and Regional Services – which should give an idea of just how important it is. The 172 square kilometre marine reserve surrounding the ocean speck is rather more important, however. Around 16 per cent of Australia's fish species can be found there.

You're only going to get into that reserve if you're an Indonesian fisherman with a special licence or an Australian government official monitoring said Indonesian fishermen from a patrol boat.

Accessible alternative: Want wildlife in a remote Indian Ocean territory? Then go for Christmas Island. There's excellent diving and bird-watching, while the annual red crab migration is one of nature's greatest spectacles.

Elliot Price Conservation Park

Anywhere else, the 63,645 hectare Elliott Price Conservation Park would be regarded as gigantic. But for Lake Eyre, it's a relatively small chunk. Deliberately set aside as an area for wildlife and wilderness (translation: lots and lots of salt) to do their thing undisturbed, the conservation park covers the Hunt Peninsula and Brooks Island.

Vehicle access is prohibited, but given that there are no roads for miles around, it'd take a remarkable effort to get one there in the first place.

Accessible alternative: 4WD tracks to parts of the Lake Eyre National Park lead from William Creek and Marree, and there's a campsite on the edge of the lake at Halligan Point. Otherwise, take it in by air. GSL Aviation offers scenic flights over the lake from Marree.

The Woomera Prohibited Area

Across the wilds of outback South Australia, an area the size of England is kept cordoned off from the public so that the Australian defence forces and various arms manufacturers can practice blowing things up.

The Woomera Prohibited Area is divided into zones. Some are only out of bounds for part of the year. But the red zone just to the north of the Stuart Highway between Woomera and Glendambo is a complete no-no, full of old bits of metal you really don't want to pick up.

Accessible alternative: The Stuart Highway cuts through the prohibited area, but you're not allowed to venture off the highway without a permit from the Department of Defence. It's possible to get a heavily glossed-over version of what's going on inside Woomera's Heritage and Visitor Centre, however. Curiously, the displays are keener on explaining the area's space research pedigree than the weapons testing.

Albatross Island

One of only three breeding sites in the world for the vulnerable Shy Albatross, this tiny Bass Strait island is a Tasmanian state nature reserve. Public access is restricted so that the birds can breed in peace, but even if it wasn't, the boat ride over there would put off all but the hardiest of visitors. Rough seas and lack of mooring make it tough to get at, even if the Parks and Wildlife Service gives you rare permission to go.

Accessible alternative: Stay at the homestead on nearby Three Hummock Island, and take in a seabird cornucopia in between kayaking, fishing and snorkelling outings.

Read: Worldwide: 10 places you will never visit