Geocaching in Hawaii: Earth Cache at Diamond Head State Monument in Honolulu, O’ahu

With plans to earn the Hawaii State geocaching souvenir on our family vacation to the the middle of the Pacific Ocean, we consulted for a variety of cache types that allowed for sufficient educational opportunities on both O’ahu and The Big Island. As luck would have it,the Diamond Head Crater Earth Cache popped up within a short drive of our hotel in nearby Waikiki.

Observing Tuff Rock

The most recognized geological landmark in Hawaii, the Diamond Head Crater is one of three tuff cones on O’ahu formed during volcanic eruptions of the Ko’olau Mountains that began about 300,000 years ago. The name for the type of rock formed from consolidated volcanic ash that is ejected during a volcanic eruption, tuff cones form around the center of the volcanic activity.

Where to Stay

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An ideal location for an Earth Cache—a special type of geocache administered by the Geological Society of America—we printed the entire thirteen page geocache description and formulated a plan of attack while on the airplane. Unique in their requirement to teach an Earth Science lesson and require geocachers to participate in an educational task specific to unique geological site, the Diamond Head Crater Earth Cache had us reading pamphlets and signs, noting the color and texture of the tuff rock as it changes up the trail, and measuring elevation differences using a GPS device.

Pedestrians walking up and down the dirt trail.

Open daily from 6:00AM to 6:00PM, admission to Diamond Head State Monument costs $5/vehicle or $1/person if you walk in through the main gate. A 1.6 mile round-trip climb takes you 560 feet above the crater floor and portions of the trail are unpaved and best navigated wearing sturdy shoes. Arriving at 6:30 AM, we found the parking lot filling with large group tour buses and other groups of zombie-eyed tourists also awake since 4AM. Carrying water, wearing hats, and packing snacks and digital gear in a backpack, we matched the park pamphlet map up with questions identified on the geocache description page.

99 stairs!

Walking up the paved walkway (last call on indoor plumbing and bathrooms for the next 1.5 to 2 hours) we soon  met up with the weaving and winding dirt trail. Note that the lookout point at Area 4 is a wonderful spot for a photo and water break. After this point, you face two stairways worthy of their own StairMaster workout. Between the stairways is a 225-foot long lighted tunnel. After the stairways is…more stairs. An alternate “easy” path after the tunnel and before the killer stairs is a paved walkway leading to more stairs. Eventually you will climb up—and out of— a building once serving as an active Fire Control Station when the crater housed five military batteries.

Honolulu From the Observation Station

Worth the calorie burn, the view from both the Fire Control Station and the Observation Station is as breathtaking as it is rewarding. Look West and you will see the Honolulu skyline; East is the 350-acre crater in all its inactive magnificence. Catching our breath and finding a Traditional Geocache (spoiler alert if you look at the photos below) before the return trip, remember to make appropriate elevation measurements and geological observations before you go. But wait, there’s more!: A Virtual Geocache can also be logged before venturing out for more.

About the Author

Julie Henning
Julie Henning is a freelance writer and journalist based out of Eugene, Oregon. She is a member of the Society of American Travel Writers and owner of the family-travel website She is a recent past member of the Midwest Travel Writers Association and the Association for Great Lakes Outdoor Writers. Julie is the Oregon Coast destination specialist for Bindu Media, an itinerary-focused website launching in Spring 2016 and featuring the work of 200+ professional, indie travel writers. Julie has been published in the Milwaukee Journal Sentinel, the Wisconsin State Journal, The Daily Journal (Kankakee, Illinois), the Rochester Post Bulletin, Wisconsin Natural Resources (DNR) Magazine, Sustainable Chicago Magazine, Group Tour Magazine, Student Group Tour Magazine, Silent Sports Magazine, Intercom Magazine,, and FTF Geocacher Magazine. Julie has appeared on Wisconsin Public Radio, Ohio Public Radio, and KCBX FM Central Coast Radio and is an affiliate producer with the Journeys of Discovery with Tom Wilmer, a National Public Radio travel podcast. She has blogged for, Travel Oregon, and VISIT Milwaukee. Julie travels with her three kids and black lab as much as possible and lives by the motto, "Not all who wander are lost." Check out some of her best work at

3 Comments on "Geocaching in Hawaii: Earth Cache at Diamond Head State Monument in Honolulu, O’ahu"

  1. What a fun and educational activity! We’ve never done geocaching but this has got to be one of the best places to do it. We did this hike a few years ago when my kids were toddlers which was not as enjoyable as we hoped. It was worth the climb for those stunning views though. We’re going back soon and would love to try geocaching there. Thanks for the tips!

  2. Geocaching is such a simple activity, a brilliant way to liven up all kinds of travel experiences and so accessible on the go with the latest generation of smart phones and geocache apps. We’ve used it to tour cities, add interest to a walk or bike ride, to find special places like earth caches. And with the caches graded you can find something to suit any level of interest or ability. I love the way you’ve used it to lead to educational spots. I’ve found it a great way to get reluctant kids to ‘boring’ places on the pretext of a treasure hunt! Nice post 🙂

  3. Thanks Stuart. We’ve been geocaching on every road trip and have always found the coolest places not on the “beaten path.”

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