The Thurston Lava Tube is an extremely popular stop in Hawai'i Volcanoes National Park along the Crater Rim Drive just beyond the Kīlauea Iki Trailhead. There is a mostly paved loop trail that leaves from the parking area, drops down to and through the lava tube, and winds back in less than half a mile, making this an ideal stop on a longer tour of the park. Along the way you'll have the opportunity to see some of the lush forest life that thrives here outside of the blast zones. While there is one overlook at the beginning of the walk, views are scarce due to the elevation and vegetation. But the main attraction, the lava tube also known as Nāhuku and renamed for newspaper publisher Lorrin Thurston in 1913, does not disappoint.
Lava tubes form as molten lava continues to flows beneath the surface of the earth or, frequently, the hardened crust of a superficial lava layer. As the current pushes through, the external portions of the flow cool at a faster rate, eventually solidifying and forming a shell around the molten lava. Once a tube forms, the original flow may disappear entirely only to be replaced during another period of activity during which lava may move down the same artery.
This 500-year-old tube is lit throughout the main path, though an unlit portion exists for the adventurous near the exit. The path undulates a bit but remains wide enough to accommodate the crowds and level enough that you can afford to look around at the walls and ceiling. The cave was once rich with stalactites, but early visitors stole them all.
Congestion here is very high, and it is well worth the effort to avoid peak crowds. Arrive early to see the area before the tour groups cycle through, and pack plenty of patience as you negotiate the parking area near Crater Rim Drive. Alternately, park at the overlook for the Kīlauea Iki Crater and walk the trail down to the lava tube.