Thurston Lava Tube Guide: Hawaii Volcanoes National Park

Nāhuku, also known as the Thurston Lava Tube, is a 500-year-old lava cave in Hawaiʻi Volcanoes National Park. The trailhead is about 1.5 miles past the entrance to park, south on Crater Rim Drive.

The trailhead’s parking lot is minimal, and you will likely not get a spot if you do not get there early. My wife and I arrived just after 9 a.m. on a beautiful late January morning. We were lucky; we got the very last spot available.

You can reach the lave tube from other parking areas, but it does extend the hike. It’s a 1.5-mile round-trip walk from the Kīlauea Iki Overlook or a 6.0-mile round-trip from Devastation Trailhead.

Trail Name: Thurston Lava Tube Trail
Trailhead Location: Nāhuku Parking Lot
Distance: 0.4 Miles Roundtrip
Difficulty: Easy
Elevation Gain: ~50 Feet
Type: Loop
Features: Cave
Dogs: No

Hiking Nāhuku or the Thurston Lava Tube

From the parking right next to the trailheads, it’s an easy 0.4-mile loop hike. After we got out of the car, we had a quick drink and headed down the trail. The trail is at an altitude of 3,900 feet on Kīlauea Crater but only has a little over 60 feet of elevation gain.

We headed down the well-worn trail through a verdant rainforest towards the cave entrance. The forest was thick and burst with sounds from ample birds. Though we were only able to spot a few, you could certainly hear them.

As we arrived at the entrance of the cave, there was a sign explaining how Nāhuku came to be.

How Lava Tubes are formed

Lava tubes form from lava flows. Large rivers of lava flow in natural channels that they create. The fast-moving center currents keep the core hot while the slower-moving edges cool and begin to thicken.

As the surface cools, the top of the flow crusts over from the sides, similar to how ice forms on a river. When the crust joins, it insulates the interior flow. When the eruption stops, lava often drains from the tube and leaves the vacated tube beneath the surface.

Entering the Thurston Lava Tube

Next, we walked into the cave, which is thought to be about 500 years old. It was immediately cooler once we got into the tube. It’s crazy to think we were walking where a river of 2000-degree lava once flowed. Nāhuku, its Hawaiian name, means “the protuberances,” possibly referring to the lava drippings that once hung from the ceiling. Sadly, those disappeared due to souvenir collectors after the tube was discovered in 1913.

The hike through the tube is not that long. The ground was wet, and there were some water drips throughout. There were some spots with lower ceilings, but nothing too crazy. The lava tube does have lights, but it is a low-light environment. I recommend bringing a headlamp. We were happy to have one. The lava tube is only lit from 8 a.m. to 8 p.m. daily, so if you plan on visiting outside of those hours, bring light sources.

How long does it take to hike Thurston Lava Tube?

The entire trail took us less than a half hour. But that said, we were not in a rush, took plenty of pictures, and unsuccessfully tried to see all the songbirds.