Kaumana Caves is a hidden gem located just outside the city of Hilo. Upon reaching the parking lot, visitors will likely question whether or not they are in the right place, as the entrance is nothing extraordinary. Across the road, a small staircase leads down into a collapsed portion of a lava tube that is unmaintained (no lights and insecure footing) and sure to make the Thurston Lava Tube look like a walk in the park. Formed by a lava flow from the Mauna Loa volcano back in the 1800s, the main tube of Kaumana Caves totals a distance of 25 miles underground.
From the entrance there are two directions in which adventurous visitors can explore. The left tube appears to be smaller from the entrance; however, a tight opening leads to a long, dark portion of the tube that snakes its way underground and at times requires some scrambling over rocks. It terminates at another collapsed section of the tube. Through the opening in the ceiling, light pours in and roots reach down, creating an eerie tropical setting. A small footpath at the end leads back to the road from above, or the cave can be followed back to the start.
The right section of the tube has a much larger opening and is usually dripping from above. The ambient light from the entrance fades quickly and the air becomes stagnant and muggy as the walls become closer together. This section of the tube is much longer than the left section, and almost 2 miles of underground tunnel being open to the public. Along the way visitors will encounter unique lava formations as well as some eerie graffiti, plenty of darkness and sometimes mud. Avoid exploring deep into the cave during periods of heavy rain because they can be known to overflow in some places. Unlike karst limestone caves, lava tubes are relatively straight and do little branching, so getting lost is an unlikely issue, but always use good judgment when entering the cave.
The cave entrance is free to the public and has restrooms and picnic tables available. Be sure to bring a good flashlight or head lamp (and a backup) as well as sturdy shoes.