Koko Crater Arch via Halona Blowhole Lookout

Park at the Halona Blowhole lookout and carefully cross the highway.. Walk west, towards Hawai'i Kai, and in a hundred feet or so you will pass mile marker 15, the trail starts on the rocks just past this marker. Carefully make your way up the rocky hill and onto the ridge, here you will find a trail: it is not necessarily well defined, so just head up the center of the ridge. The arch is hard to see from at the start but it lies on this ridge and will pop out as you make your way further along the trail. 

The trail becomes more well defined as you turn towards the arch and if you follow the ridge it will force you to climb up and over the arch. This way becomes very steep and those fearful of heights may choose to venture another way... As you approach the arch, but before you climb up and over, you can climb off the right or left side of the ridge and approach the arch from below* (this is likely the preferred method as you are then able to look through the arch and down onto the water). 

*The trail on the ridge is rocky but solid, this changes are you get off the ridge and head under the arch: the ground is rocky and loose and it is easy to slip so extra caution is advised here. 

Once here you can take some pretty neat pictures with the natural frame of the arch. You will find nice views of the infamous Sandy's beach, as well as Halona cove and Hanauma Bay. 

The hike up to the arch does not take long (20 minutes or so). This is where many people stop and turn around... but those with more time and looking for added adventure can continue up past the arch towards the summit of Koko head. The trail is fairly steep and slippery but in a short time you will be standing on the ridge of the crater. You can follow the ridge down towards Sandy's beach or up towards the summit. This is a much different path to the summit than the standard staircase but can make for a very fun alternative!