Caving in Queensland's 'lava tubes' is a unique outback experience

Enter an intriguing subterranean world in outback Queensland, into ancient lava caves thousands of years in the making.

A man walking through a lava tube in Undara Volcanic National Park
  • Alana Schetzer
  • March 2020

I’m standing at the mouth of a cave that was once a heaving river of molten lava, snaking a red-hot path across the ground during an eruption almost 200,000 years ago.

“This isn’t like any cave I’ve ever seen,” says John, an American tourist taking part in today’s adventure. “Most caves you feel kind of trapped inside, like really enclosed, but I don’t feel like that in here.”

I nod in agreement. What I notice, apart from the bursts of light that act as nature’s spotlight, is that the terrain in front of me is not the scorched, barren landscape you might expect. In fact, these lava tubes, which are part of Undara Volcanic National Park in tropical North Queensland, are surrounded by dense, green and dry rainforest. The trees and vegetation have, like the lava before them, taken over the land as far as the eye can see.

Bats flying through a lava tube Undara Volcanic National Park surrounded by greenery
The national park is surrounded by tropical rainforest.

Located about 300km south-west of Cairns, these lava tubes are an ancient relic of a bygone era, a time when there were more than 150 volcanoes dotted across the landscape (what is now called outback Queensland) and humans were yet to call this country home. Some 190,000 years ago a volcano, dubbed Undara Volcano, erupted, causing 23 billion cubic litres of lava to burn and flow across 1550-square kilometres.

As the lava moved across the earth, it cooled at different rates, with the outer layer cooling faster than the inner core (kind of like a lava cannoli), creating an outer crust. The result is a very different natural attraction to Queensland’s oceans, reefs and waterfalls; this one is on dry land, partly in the dark, and is one of the world’s longest trails of solidified lava from a single volcano.

In order to protect this delicate environment, visitors are only allowed to inspect the tubes as part of an accredited tour, so I opt for the “Wind Tunnel Explorer”, a two-hour journey that partly does away with walking platforms and involves some climbing over rocks.

A lava tube in Undara Volcanic National Park
The lava tubes were formed as a result of volcanic eruptions thousands of years ago.

It seems a shame to delve into a cave when the ever-reliable Queensland sun is doing what it does best but the first thing you notice is that these hollows aren’t of the dark and dank variety. Over many, many years, various parts of the cave system have collapsed, opening up areas for light to reach in and vine thickets to grow. There are some enormous light wells that act like cinema screen-sized windows to the lush, green vines and trees that have bound themselves to the rocks. Even as you explore areas that are quite dark, you know sunlight and a beautifully ragged garden aren’t far away. It’s like walking through your own dimly lit fairytale wonderland.

Up close, the surface of the tubes is startling to look at – you can see colour and textures play games with you. Depending on which part of the tube you are in, you can be surrounded by deep browns with chalky elements, or flaming reds and bright oranges, not unlike the molten lava that created them.

Our walking pace is slow as our Undara Experience guide, armed with a torch, explains the explosive history of the caves and how they were formed.

The visitor centre at Undara Volcanic National Park
You can explore Undara central with the help of an expert guide.

He points out various parts of the lava tubes that are an ecological haven for dozens of animals such as the eastern cave bat, little red flying fox and the delightfully named blue-faced honeyeater bird.

Given the enormous size of the caves – there are two main branches, the shortest being about 16km – we don’t have time to see the whole system. And some areas aren’t safe due to their high carbon dioxide levels, so each guided tour focuses on small, harmless and accessible parts.

The tour guides are exactly what you hope they will be – friendly, knowledgeable and always up for a joke, even of the “dad” variety. And I have plenty.

“Hey,” I say. “Do you know what the girl volcano said to the boy volcano?”

“I don’t know, actually,” our guide responds.

“I lava you!”

Despite how bad my joke is, I’m pretty sure someone chuckled. Hopefully at the joke.

Standing in these caves, you feel incredibly small and rather in awe of nature’s own architecture; their sheer size dwarfs everyone, with the biggest caves stretching up to 21.2 metres in width and 10 metres in height.

A group of people standing in a lava tube
These lava tube caves are located around four hours from Cairns.

The caves are maze-like and yet they have a “flow” to them that makes sense; flow being the operative word, as you’re following the actual path of the molten lava that scientists estimate flowed at a temperature of around 1200°C. And it’s hard not to imagine what it must have looked and felt like at the time the volcano erupted.

The walk itself is pretty easy (and I’m not particularly fit). The rocks we scramble over aren’t big. And the experience makes me feel more adventurous than I actually am.

As the national park is about four hours west of Cairns, it’s a good idea to stay the night so you have time to take everything in. Accommodation options include a caravan and camping park, cabins with the necessary creature comforts, and quirky restored railway carriages, which are set under the shade of bushy green trees.

“Undara” is a local Aboriginal word meaning “long way”, and while Undara Volcanic National Park is certainly a decent distance from anywhere, it’s the lengthy passage of time that I can see manifested in front of me that makes a lasting impression. The cave system and its surrounds are the physical embodiment of what nature and time can do; to both destroy and create, and it’s a rather astonishing thing to see.