Diamond Head, of course, makes the striking, world-famous backdrop to Waikiki Beach: probably Hawaii’s single most famous vista. This picturesque—and somewhat imposing—the volcanic edifice isn’t just dreamy to look at. It draws hikers up to its craggy crown on a classic day hike out of Honolulu.
This instantly recognizable landform is a tuff cone, formed from a volcanic explosion that dropped blasted-apart rock fragments and ash as a rim around the vent. Geologists date the Diamond Head eruption, on the southeastern edge of Oahu’s Koolau Volcano, to about 300,000 years ago. That’s actually long after the main period of Koolau activity, which took place a few million years back. Diamond Head forms a lopsided crater, its rim highest on the southwestern edge where prevailing winds piled the most volcanic debris. It’s such a superb, significant example of a tuff cone that this craggy, grooved battlement was designated a National Natural Landmark in 1968.
The crater earned its Western name because of the glinting of its calcite crystals. Native Hawaiians, however, called the landmark Leahi: “brow of the ahi,” on account of its resemblance to a yellowfin tuna’s profile. (That name, tradition says, was bestowed by the volcano goddess Pele’s sister, Hiiaka.) In bygone days, Hawaiians lit fires atop Leahi to assist with navigation and erected a temple up top honoring the god of wind.
Its oceanfront location and strategic height meant Diamond Head was destined for military development. The federal government purchased the land in 1904 and set to fortify it with batteries, tunnels, and the summit Fire Control System. Leahi was a linchpin of Oahu’s coastal artillery defense system, though its guns never ended up firing.
The 0.8-mile trail leading from the Diamond Head crater floor to its summit dates from those early days of defensive buildup. It’s a moderate undertaking involving 560 feet of elevation gain. This is an open, semi-arid landscape, and you’ll definitely want sun protection and plenty of water. But also pack a jacket in case of breezy conditions or showers.
The trailhead adjoins the parking lot in Diamond Head State Monument. The route is an interesting blend of surfaces and surrounds. It begins as a concrete walkway, soon transitioning to volcanic tuff as it switchbacks upslope.
Multiple stairway sections help accomplish the climb, and there’s even a 225-foot-long tunnel (electrically lit). Landings and lookouts serve up plenty of scenery, with the homerun view awaiting atop the Fire Control Station’s top level. You’ll tackle a spiral staircase to reach that ultimate summit, set at 761 feet.
The sight lines from the top are ravishing. Enjoy a bird’s-eye view of Waikiki and Honolulu, with Koko Head off to the east. Gaze out to the twin spines of Oahu: the Waianae and Koolau ranges, eroded ramparts of the island’s two formative shield volcanoes. And peer offshore to the distant Pacific horizon, where clear conditions afford looks at Maui, Molokai, and Lanai.
You’ll ideally want to carve out two hours or so for the Diamond Head hike, which gives you time to catch your breath and savor the views from multiple vantages. You can also expect some congestion along the trail, not least in the stairway sections, which can slow things down. No need to rush the climb up Hawaii’s best-known landform, though!
How To Get There:
On the east side of Honolulu’s Diamond Head Road, between Makapuu Avenue and 18th Avenue. To park, there are many parking lots nearby if you want to hike the trail. There is also a parking lot through the side of the crater. You might have to pay a small fee for parking.
The gate at Diamond Head State Monument closes at 6 PM, so don’t tackle this hike any later than 4:30 PM.