People who visit Hawaii are quite familiar with the white sandy beaches and lush forested hills so frequently depicted on postcards and promotional materials, but one landscape feature many aren’t aware of is the network of lava tubes crisscrossing just beneath their feet. Parts of these Big Island lava tubes exist as massive tunnels in the ground that one can walk throughout, much like any traditionally large cave. It is a unique experience and one certainly worthy of putting on your bucket list for things to do when you visit the Big Island.
How the Big Island Lava Tubes Formed
The most common way for caves and underground tunnels to form is through the long-term erosion of rock by water. Tunnels and caves formed this way take 100,000 years or more before they become a discernable space. In sharp contrast, many of the lava tubes Big Island were formed within just a couple of months!
The speed of Big Island lava tube formations is due to their being the direct result of ground-changing volcanic eruptions. There were six volcanoes that coalesced to form the Big Island, and since that formation, their eruptions continued to shape this largest of the Hawaiian islands. Each eruption spews out a combination of molten rock and gas that instantly eats away at the land. That molten lava flows down the volcano’s sides, sometimes all the way to the ocean — but not all the lava will drop into the sea.
Much of the lava from a volcanic eruption will remain on the land of Hawaii as it comes to hardened rest. The exterior of a massive lava flow will harden first, slowing and changing into a crust, but the inside remains hot and continues to move and burn away at whatever stands in its way. That movement creates a hollow in the molten tube’s wake, some of which will push up or out and others that will push down, deep into the ground beneath creating deep caverns stretching below even the sea. When the still-molten lava finally pushes out from the exterior-layered crust, it creates a gaping entrance that opens the rest of the tube to the world. When everything finally cools, what is left are hollow volcanic tubes that look and feel much like a natural underground subway system.
The Importance of Volcanic Tubes
The volcanic lava tubes of the Big Island have great significance. They have their own ecology with several unique animal and plant species that call these tubes home. Additionally, the largest of these tubes served as important sites for Hawaii’s indigenous populations. Their cavernous interiors, often well colder than the upside environment, were frequently used for food storage and shelter to escape the hottest days as well as the most demanding storms. A few select locations were used by ancient Hawaiian cultures as burial sites and religious locations for use in special ceremonies. These holier locations are closed to the public out of respect.
Bucket-List Lava Tubes to Visit on the Big Island
But while there are lava tubes and lava zones on the Big Island that visitors are not allowed to traverse due to compact size or holy significance, there are plenty that are not so off-limits. The following is a look at the best of those options to visit; ones the adventurer at heart will want to put on their Hawaiian bucket list:
The Nahuku-Thurston Lava Tube in Hawaii Volcanoes National Park
Located within the Big Island’s Hawaii Volcanoes National Park, this lava tube is the most readily accessible one on our list. When the park was first opened, this lava tube was best known as the Thurston Lava Tube due to it being “discovered” by a local newspaper publisher and park advocate by the name of Lorrin Thurston in 1913. But in recent years, the preferred name has included the original discovers of this lava tube: Ancient Hawaiians who named it Nahuku, meaning “the protuberances.”
Entering the Nahuku-Thurston Lava Tube feels like entering a massive cave. The trek into the tube takes you through a tropical landscape bordered by massive ferns and into a tube that is tall enough for adults to stride through (although there are some lower overhangs for which one will want to watch their head). Some parts of the tube have ceilings as high as 20 feet and wide enough for several adults to link arms and walk through.
You can visit the Nahuku-Thurston Lava Tube any hour of day or night (yes, really, it’s open to the public 24 hours a day), but you will only have their installed lights turned on between 8 am and 8 pm. If you go after these hours, make sure to bring a flashlight or headlamp.
Kaumana Caves Near Hilo
This Big Island lava tube is located in a more residential area and is one of the newest lava tubes in Hawaii. Called the Kaumana Caves, this is a gigantic lava tube cave that was formed by the 1881 eruption of Mauna Loa. Entrance into the Kaumana Caves is free, with parking for the park it resides in on Kaumana Drive, west of downtown Hilo.
To enter the Kaumana Caves, you will walk down a set of stairs into a tropical ravine. These stairs are steep and once you duck your head under to enter the caverns, you are going to be in complete darkness, even during the height of day. A headlamp or flashlight is a must. There are two parts of this cave, a left side and a right side. Both are tubes that you can follow completely to their exit, where they wrap around back to the start so that you can follow the other.
Located in the west part of the Big Island, the Kazumura Cave offers a very unique lava hike Big Island in that it is the longest possible hike one can do. Not just the longest in Hawaii, but the longest in the world! This lava tube Big Island stretches for an incredible 42.5 miles, a portion of which is explodable if you go through the private tour company of Kazumura Cave Tours.
Via the Kazumura Cave Tours, you can explore this unique lava tube in three ways: A basic introduction into the most accessible part of the caverns, a two-mile lava hike that reaches the Pit Room, which is a giant collapsed cave sink, and what is called a Maze Tour for the truly adventurous. This Maze Tour takes hikers deep into the cave, with steep descents that require repelling assist ropes, and into famed parts of Kazumura Cave like Red Column falls and Sexton Maze.
While you can find a Big Island lava zone map showcasing the different parts and some entrances for the Kazumura Cave, none are publicly accessible except via a licensed tour. This is structured to help reduce human impact and prevent injuries due to the dangers inherent of this lengthy, ancient cavern.
Kula Kai Caverns
The Kula Kai Caverns is another collection of lava tubes that is only accessible via a licensed tour operator. You’ll find this underground network on the south side of the island, near the community of Ocean View. The Kula Kai Caverns are a part of a larger network of lava tube tunnels called the Kipuka Kanohina Cave System that stretches beneath a significant part of the island’s southern lands and is the second-longest lava tube in the world after Kazumura (yes, both the first and second-longest lava tubes in the world exist right here on the Big Island). Many parts of its underground network are restricted as they contain sensitive Hawaiian artifacts and other evidence of ancient human habitation and civilization.
Of the parts that are open to the general public, the company that operates the tours for Kula Kai Caverns offers the following options:
- The Lighted Trail Tour features an easy underground hike along a lighted trail. This hike takes about 30 minutes. You can go beyond the lighted trail for a bit extra in an upgrade entitled The Archeological Tour.
- The Crawl Tour, which, as its name suggests, requires some ducking and crawling to get into more remote passages of the Kula Kai Caverns. This one is a bit more difficult but also quite exciting for those looking to experience the further recesses of a lava tube with an experienced guide.
- The Two-Hour Tour features a more extensive guided tour of the Kula Kai Caverns and is a must for those interested in learning more about its history and geological formations.
Learn More About the Unique Locations & Activities Possible on the Big Island of Hawaii
There are also plenty of other ways to experience how the volcanoes of Hawaii shape its land, including seeing the process in person via a Big Island lava boat tour that will take guests up close and personal to ongoing molten lava flows. You can learn more about these unique types of adventures and many others by visiting our other pages. We aim to get you all the best Hawaii visitor information you need to book that dream vacation you and your family or friends will be talking about for many, many years to come!