The Kaumana Lava Tubes are among the most accessible lava tube systems in Hawaii and, unusually, completely free and unguarded. A short staircase descends from a roadside park into a collapse pit, and from there you can walk into the tubes in both directions. The main accessible section extends a few hundred metres; the tube narrows and requires crawling to go further. Bring a headlamp — the tubes are pitch dark — and wear clothes you don't mind getting dirty.
The tubes are cool and damp, a pleasant contrast to the heat outside. Ferns and other plants grow in the entrance area where light penetrates. The floor is uneven lava rock, so wear sturdy shoes. Because there's no commercial operation here, you get the tubes largely to yourself except on weekends. Located about 7 km from downtown Hilo on Kaumana Drive.