We drove from the Kīlauea Iki Overlook around the other way to get to the Thurston Lava Tube, a huge tunnel left behind when the lava drained away.

Thurston Lava Tube
This huge tunnel was left behind when a subterranean river of lava drained away. An easy trail runs through the tube and a grove of giant ferns.
DK Eyewitness Travel Hawaii

Trail to Thurston Lava Tube, Hawaii Volcanoes National Park - The Underground World of Caves
Trail to Thurston Lava Tube
Trail to Thurston Lava Tube, Hawaii Volcanoes National Park - The Underground World of Caves
Trail to Thurston Lava Tube

First there is a short walk through giant ferns. We expected to see a dinosaur. It was raining, but not too bad and we were out of the wind.

Thurston Lava Tube Formation, Hawaii Volcanoes National Park of a Lava Tube - The Underground World of Caves
Thurston Lava Tube
Formation of a Lava Tube

Thurston Lava Tube
Formation of a Lava Tube

  • Most lava tubes form in molten pahoehoe lava flows.
  • Exposed to air, the top portion of a lava stream often solidifies and insulates the underlying fluid lava, which continues flowing beneath its hardening crust.
  • As eruptive activity diminishes the supply of new lava stops.
  • The molten lava then drains out like water from a shut off hose.

Trail Facts

This loop trail passes through a section of Thurston Lava Tube and returns to the parking area. Walking time is about twenty minutes. Some portions are moderately steep, but the trail is short. Exiting the tube, you will walk through part of a Special Ecological Area. This 25-acre unit of montane rain forest is a sample of native Hawaiian forest, free of destructive feral pigs and most non-native plants.

The fern-shrouded entrance leads into a well-lighted section of a prehistoric lava tube. As you walk this short segment you will follow the path of the molten river which formed the tube centuries ago. Ledges or benches such as these can be seen in Thurston Lava Tube. They form as the lava supply diminishes and mark different levels of lava supply through the tube.

Nahuku extends 334 meters beyond this point. You are invited to explore this undeveloped section of the lava tube where natural features have not been disturbed.

  • You will need a flashlight
  • Watch your footing
  • Be aware of low ceilings
  • Tread lightly on these fragile resources
  • Do not disturb toots or geological features
Stairs into Nāhuku, the Thurston Lava Tube, Hawaii Volcanoes National Park - The Underground World of Caves
Stairs into Nāhuku, the Thurston Lava Tube
Entrance to Thurston Lava Tube, Hawaii Volcanoes National Park - The Underground World of Caves
Entrance to Thurston Lava Tube
Entrance to Thurston Lava Tube, Hawaii Volcanoes National Park - The Underground World of Caves
Entrance to Thurston Lava Tube

The lava tube was much larger than I expected!

Roots hanging down into Thurston Lava Tube, Hawaii Volcanoes National Park - The Underground World of Caves
Roots hanging down into Thurston Lava Tube
Tour of Thurston Lava Tube, Hawaii Volcanoes National Park - The Underground World of Caves
Tour of Thurston Lava Tube

I had no idea it was so huge. It did not rain on us underground.

Locked entrance to the rest of the lava tube, Hawaii Volcanoes National Park - The Underground World of Caves
Locked entrance to the rest of the lava tube
Locked off portion of Thurston Lava Tube, Hawaii Volcanoes National Park - The Underground World of Caves
Locked off portion of Thurston Lava Tube

Part of the lava tubes is out of bounds without permission.

Stairs from Thurston Lava Tube, Hawaii Volcanoes National Park - The Underground World of Caves
Stairs from Thurston Lava Tube
Tour of Thurston Lava Tube, Hawaii Volcanoes National Park - The Underground World of Caves
Tour of Thurston Lava Tube
Tour of Thurston Lava Tube, Hawaii Volcanoes National Park - The Underground World of Caves
Tour of Thurston Lava Tube
Stairs from Thurston Lava Tube, Hawaii Volcanoes National Park - The Underground World of Caves
Stairs from Thurston Lava Tube

Thurston Lava Tube Trail
Thurston Lava Tube can be accessed via an easy 15-minute loop trail. The paved trail begins with a steep descent into the rainforest, dense with towering green ferns. The trail then leads visitors to a pit crater where it is possible to enter the lava tube. Formed when the exterior of a lava flow cooled to a crust while the still-molten interior magma flowed out, the tube resembles a giant tunnel. Walk through the 600-ft winding passage takes about ten minutes. Signs posted along the trail provide information about plants and animals that can be seen in the area.
DK Eyewitness Travel Hawaii

Who was Thurston?

The Thurston Lava Tube was discovered in 1913 by Lorrin Thurston, the grandson of Asa and Lucy Goodale Thurston, two of the first Christian missionaries to Hawaii.

Lorrin Thurston was also a volcano enthusiast. In 1891, he bought the Volcano House hotel at the rim of Kīlauea. He expanded it before he sold to George Lycurgus in 1902.

Thurston was friends with Dr. Thomas Jaggar, an early volcanologist. He raised the money to fund the Hawaiian Volcano Observatory in 1912.

Thurston owned a newspaper and heavily promoted creating a Volcano National Park. Thurston was at Columbia with President Theodore Roosevelt. He was able to get support from Roosevelt, John Muir, and Senator Henry Cabot Lodge. Hawaiʻi Volcanoes National Park was formed in 1916.

When the Thurston Lava Tube was found, the roof was covered with lava stalactites, but souvenir collectors “picked” them. People used to believe stalactites grew back.

Interested in Volcanos?
Find out more: Curiosity Trek – Hawaii >

Thurston Lava Tube, Hawaii Volcanoes National Park