One of the most advertised must-see attractions on Oahu is Diamond Head State Monument. At the time of this writing, TripAdvisor has 93% of contributors giving the attraction a "thumbs up" and it's ranked #9 out of 123 Honolulu attractions. EveryTrail.com states, "The Diamond Head Summit trail hike is likely the most popular hike in Oahu, and for good reason."
Diamond Head is located on the southeast portion of Oahu and just east of Honolulu. It can be seen on the upper (slightly left of center) portion of the next photograph (taken from Pu'u 'Ualaka'a State Wayside view point).
Some hikes are great because of the scenery and experience of the hike itself while some hikes are great because of the ultimate reward that awaits at the finish of the hike (usually a view or waterfall or something else special at the summit). The Diamond Head Summit Trail hike, in my opinion, is in the latter category. After living in and hiking in Colorado and Utah and after hiking Maui's Pipiwai Trail just a couple days earlier, I may have had a higher than normal threshold for what makes a hike interesting in and of itself, but I felt like the Diamond Head Crater hike itself was largely unmemorable. Fortunately, the hike's ultimate destination is what makes it memorable. The next photograph shows a view of Honolulu and the coastline from the top of the crater.
The overall difficulty rating of this Diamond Head Summit Trail is often described as "moderate." The hike is very easy (flat on a wide sidewalk) at first, starts to gain some elevation with some gradually climbing switch backs, and then has a steep staircase that presents the most difficult portion of the hike. The surface is normally smooth (concrete, steel, and wood) to slightly bumpy (hard earth) to uneven (loose earth) with relatively little difficult terrain. In addition, there are some dark tunnels and some spots where taller individuals will have to lower their heads a bit. It is difficult to describe the hike precisely, but I've included some photographs in this post to provide an idea of what it's like. I'm not including any photographs of the flat beginning of the hike, but the next two photographs show the gradually inclining part of the hike that includes multiple switch backs. The best way to get a graphical idea of what the hike involves is to reference the graphic on the second page of the Diamond Head State Monument brochure.
There are a couple places where the hiker goes into structures. One of these, a 225-foot tunnel, is dimly lighted, but light visible from both ends on a sunny day makes it very manageable without a flash light.
The most difficult aspect of the hike is the steep staircase near the top. The Diamond Head State Monument brochure provides details on the sets of stairs, including mention of "steep stairway of 74 concrete steps" and "second stairway consisting of 99 steep steps." The next images depict this staircase from two perspectives (looking up from the bottom and looking down from the top).
It is the hike's summit that makes it special. The next photographs show various views from the top.
Diamond Head State Monument opens at 6 am each day. We arrived there at about 7 am on a weekend day and there were only 3 parking spots left in the main parking lot closest to the trailhead. Had we arrived even five minutes later, we'd likely have had to park at the parking lot down the road. The walk from that parking lot to the main parking lot would add very unexciting and slightly uphill walking to the overall hike.
Because this hike is well-known, is easy to access, and is itself a moderate hike, it's very popular. There were few places on the hike where I had more than a few feet between the me and the person in front of me or the person behind me. Large tour buses were stopping regularly to drop tourists off and there was a relatively steady stream of people ascending to the summit and descending from the summit.
I enjoyed hiking the Diamond Head Summit Trail and especially enjoyed the view from the summit. If I was able to visit Oahu multiple times, I'd probably not take this hike every time I visited, but I think it's definitely worth doing the first time one visits Oahu. It's a relatively short hike of 1 to 2 hours and allows one to see some spectacular views of Honolulu and the Oahu coastline.