Directions: From Kalanianiole Highway turn mauka (toward the mountain) on Laukahi Street. Continue mauka (toward the mountain) on Laukahi until you come to a security guard station. Check in with the security guard and then proceed up Laukahi until it ends. Turn left on Oko`a, following the trail signs. Park in the parking area before the cable gate and proceed on foot along the access road to the trailhead..
Trail Information: This is a dirt road / ungraded ridge trail combination which makes its ascents to the Koolau crest. Most of this trail is road-walking (paved & 4WD) and its ups and downs are not too steep. It's perfect for novice and beginning hikers or those who want to get away and see some trees. For those newbies who are interested in a taste of ungraded ridge-walking, they can continue along the ungraded section. For those who are ready to try exposed scrambles up very steep sections (typical of many Koolau ridges), the final ascent will do! Thus, this trail is perfect for someone who wants to test out their abilities (strengths and fears). The summit of the trail is the knob-like peak just behind the repeater station (the unmistakeable structure with the tall antenna).
The first 75% of the trail is human-tamed as it proceeds up man-made roadways. The first section is the Board of Water Supply access road to the water tank (0.3-mile). There you'll find the first trailhead off to the left side of the tank. After a lengthy road-walk (1.3-mile) over a wide, well-graded and maintained 4WD-road, you'll find the next trailhead (again, off to the left).
Don't expect to see landscape views for at least the first half of the entire hike - the road-walk pleasantly passes through continuous stands of pines, formosan koa, and guava trees. Occasionally, there'll be a break in the trees but not enough to afford panoramic vistas.
The views start to open up when you finally begin the ungraded trail section (0.8-mile). Here, the vegetation layer begins to subside as you climb the small humps toward the summit. The good news is that most of the steep sections along these two humps are terraced by steps. Unfortunately, the final ascent does not have these steps installed and you'll be ascending two very steep, muddy, and exposed sections. Because of this final scramble, summitting this trail is not for beginners.
Finally, you can't escape the influence of human technology on this trail. After passing the paved road, then dirt road, you'll always be traveling under or along side powerlines, passing electric poles, and in sight of (then passing) the repeater station.
Windward views from the top include Olomana, Keolu Hills, Bellows Airfield (abandoned), and Kailua in the foreground which extends to Chinaman's Hat, Ohulehule, and bits of Kaaawa Valley beyond. In the opposite direction you'll see downtown Honolulu and Waikiki, Diamond Head, the airport, and parts of the Waianae Mountains, from Kalaeloa and Ko Olina to Puu Kaua.
Miscellaneous Information: The final 25% of the trail is comprised of ungraded ridge to the top and includes narrowing ridgelines exposed to potential slips and falls. Be very careful on the final ascent where there are two steep and exposed sections which may be extremely muddy during rainy conditions. There are ropes to assist but always test them before using. Also, crest-walking the Koolau spine is extremely dangerous so hiking from the Wiliwilinui summit to a nearby ridge (i.e. Hawaii Loa or Mauumae) should be attempted only by experienced hikers.