Undara Lava Tubes

Undara Volcanic National Park is the traditional country of the Ewamian (pronounced You-a-min) Aboriginal people, in the McBride Volcanic Province of Queensland's Gulf Savannah. About 190,000 years ago a shield volcano erupted here: Queensland Parks estimates 23.3 cubic kilometres of lava flowed at around 1,000 cubic metres a second, sending flows more than 90km north. Lava running down valleys crusted over, flowed on underneath, then drained out, leaving tunnels; later roof collapses cut the caves and depressions you see today. More than 70 caves have been found in the park, and the system is Australia's longest.

You cannot walk into them alone. Concealed collapse holes, confusing terrain and carbon dioxide levels up to 6% in some tubes mean access is by guided tour only, booked through Discovery Resorts–Undara, Discovery Parks–Mount Surprise or Undara Lava Tube Tours. The Kalkani Crater rim is the part you can walk without a guide. Above ground it is dry savanna woodland over lava flows with vine thickets in the collapsed tubes, and at dusk thousands of bats leave the caves while spotted pythons wait at the entrances.

What to expect

Reviewed 8 November 2026

You come in off the Gulf Developmental Road, 17km past Forty Mile Scrub National Park, then 6km to a fork where the park splits: 9km right to Discovery Resorts–Undara and 6km left on all-weather gravel to the Kalkani day-use area. The road is sealed and a conventional vehicle handles it, but it corrugates, and road trains up to 50 metres long share the narrow sections, so you pull right off the bitumen to let them past. The country is dry savanna woodland over lava flows, thin eucalypts and dry grass, and it is hot: Queensland Parks nominates April to August as the preferred time and tells walkers to take water, sunscreen, a hat and protective clothing and to walk in the cooler part of the day. Fuel and supplies sit at Mount Surprise, Mount Garnet and the resort and nowhere else near the tubes, mobile coverage is unreliable through most of the park, and you take a track map from the resort reception before you walk anywhere.

The landform story is the reason you drove this far. About 190,000 years ago the shield volcano here erupted, and Queensland Parks estimates 23.3 cubic kilometres of lava flowed at around 1,000 cubic metres a second, at roughly 1,200°C, sending flows more than 90km north and over 160km north-west — the park's own comparison is that it would fill Sydney Harbour in six days. Lava confined to valleys crusted over into a roof, kept flowing underneath for tens of kilometres, then drained out; when sections of the roof later collapsed, the caves and depressions of today formed, and more than 70 caves have now been found. The system is Australia's longest and one of the longest in the world, and it is unusual in developing on a granitic basement. Bayliss Cave is described by Queensland Parks as one of the world's most biologically diverse caves, with at least 52 resident animal species, and the wider park holds craters, lava ponds, perennial springs and, by one regional count, about 164 volcanoes, cones and vents.

You only see the inside of the tubes with a guide, and the tours are built for it: the Archway Explorer runs 2 hours through the Archway section on boardwalks and stairs with handrails, while Undara Lava Tube Tours runs a 3-hour tour of 4 tunnels including the Arch Complex — Archway, Ewamian and Stephensons Tubes — travelling into the park by air-conditioned coach. In the tubes the light drops to whatever you carry, the walls show white and rust-red rock over a sandy floor, and the air goes still and humid; in the unventilated far ends carbon dioxide reaches up to 6%, some 200 times normal, which is exactly why unguided entry is banned. Where the roof has come down, vine-thicket rainforest grows inside the caves, and the rare white-flowered onion vine grows in the park's vine thickets. If scrambling is your thing, the Wind Tunnel Explorer takes 2 hours with a rope provided in places and asks for moderate fitness; if it is not, the operator runs a 2-hour accessible tour in Road Cave, which has ramps and a lift.

The wildlife is concentrated around the caves and the springs. Four insectivorous microbat species roost in the tubes, including the large bent-wing bat and the eastern cave bat, and Bakers Cave is a maternity site that Queensland Parks says holds about 80,000 bats at peak — at dusk thousands pour out to hunt while spotted pythons and other predators wait at the entrances for the same reason you are standing there. More than 120 bird species have been recorded, among them the vulnerable red goshawk, barking owl, pale-headed rosella and striated pardalote, and early mornings are the time for them. The antilopine wallaroo reaches its southern limit in this park and is common around Fifteen Mile Spring, with the northern quoll also recorded. Wind Tunnel Complex and Barkers Cave are restricted from November to February to protect the breeding bats, so a summer visit removes the best wildlife show along with the caves.