Koloa Falls

Best Hike I Have Done on Oahu (So Far)
A few buddies of mine and I did this a few weeks. We are active duty soldiers, so you could say we are in shape. We try to hike once maybe twice each weekend. The hike is approximately 8 miles and very treacherous. The hike is amazing. It starts with a good portion of steep uphill to a lookout that views everything you just walked from. (Hau’ula, the valley you are hiking into, and the coast).
After that the descent begins for about 25 minutes (for us). You arrive at the bottom of the valley, and prepare to cross the stream in the valley 23 or so times. The tape that marks the trail actually counts off the crossings. Once you hit 23 you will start the last leg to the fork in the stream that goes towards Koloa and Kalo Falls I believe (Don’t quote me). If you go right to Koloa Falls (this is the falls worth going to). It is about a quarter of a mile, definitely not a mile like an avid hiker quoted on their review. It might feel longer, because at this point there is less of a trail, and more rocks. Once you get to the pool (first photo showed on this review) you will have to get wet. You will need to either tip top your way over to the left side of the pool, and use the ropes to climb up to Koloa Falls. Be careful the ropes are quit weathered. (They held up me and my buddy fine. I am about 193, and he is about 210) After this you will be at the base of Koloa Falls which is estimated at about 80 foot tall.
I can see how some people won’t appreciate this hike as much as others. Koloa Falls is truly beautiful. It is in the middle of the jungle, which I think is great. When we all showed it, we were the only ones there to enjoy the falls.
Other interesting things are Hawaiian O’opu in some of the deeper pools. There are also large crawdads/​crayfish in a lot of the pools. They are very interesting, they look a lot different than typical mainland crawdads. The hike is overall great. Just enjoy the wilderness.
As far as how difficult the hike is, well it left everyone in my group pretty exhausted after. We took about 6 or 7 hours to complete. We did hangout at the pool for a bit, and enjoy most of the views. Definitely wear shoes that will protect your ankles. Be prepared to get your feet wet, and the trail is very muddy.
Enjoy it.

As I sit here and read the reviews of this hike I can’t help but be amused at the second review. For someone being an «avid» hiker he sure did complain a lot about a hike that descends into a valley along a stream. I mean really, slippery rocks and mud, why not expect that? I would like to say that I just recently conducted this hike. A buddy of mine told me about it and said it was a good hike, difficult due to the boulders you have to cross. If you are looking for a nice challenging secluded hike, this is the one for you. It’s long, tiring and challenging, but the end point is wonderful. The water will feel amazing since you will be hot and humid from the trek to the fall. The trail is well marked and stream crossing points are easily identified with pink/​orange survey tape. Being close to 8 miles round trip its a good days adventure. It took me 4 hours to complete. Take water with you! I did the entire hike with no water source and still made it back in once piece, but don’t recommend people trying to follow my foot steps. As I said before, if you want a challenging secluded hike, give this one a try.

This hike isn’t for everyone. It’s a long and tedious trek, going in and out of water the entire time. Very easy to slip and fall on huge stream rocks. I agree that this is for experienced hikers only. Shoe spikes and trekking poles saved me as I maneuvered through the mud, rocks, and water. It’s about 7.5 miles rt. We did it in 5 hours, but I heard it can take 8+ if the weather is bad. The end is pretty, but not spectacular.
I enjoyed it for the workout and solitude. I went through 4 liters of water and ran out about mile 6.5. So bring a lot of water!
You must get a free hiking permit from Hawaii Reserves to be on this property. E-​mail them and they’ll assist you, or go to their office.

I too signed up just to review this hike. I will be a little biased as I was born and raised out here on this side of the island (also an avid hiker) and have done this hike numerous times. I take no offense to the other reviewer, but I will counter his poor review with what I feel is a much fairer one:
1^st off, there are no leeches (yet) here on Oahu or the in the State of Hawaii and the only parasite I can think of that would be up there would be Leptospirosis, which is in all the streams (water bound) across the state. Don’t drink ANY unfiltered stream water!
As with many hikes in Hawaii involving a stream bed, 20+ stream crossings are quite normal (at least for most valley hikes on this side of the island). As are lots of mosquitoes! Oh, and getting muddy and slipping around rocks is quite normal, too. I recommend using Tabis for stream bed hikes (tabis are Japanese foot socks, kind of like reef walkers, with a felt sole-​perfect for rock hopping).
Yes, the hike is pretty LONG. 3.5 hrs sounds about right, so plan for ALL DAY. And it also isn’t the prettiest hike, either. Its pretty much the same view for much of the hike (still nice, though). The water at the top is COLD, like every falls high up in the valley. And the end pool is not THE most spectacular (there are incredible falls out here, but I’m not telling). But its also not the worst hike!
I don’t go very often (about every 3 – 5 yrs), only because of the time it takes versus the quality of the hike ratio. I do go into the lower part of the valley a lot to do short hikes with the kids.
All in all, its still a nice, beautiful hike. The scenery is still quite nice and I love it up there because of the solitude. I would recommend this hike for UPPER INTERMEDIATE and EXPERIENCED hikers only, due to the length and being a very deep, narrow valley hike with lots of rock hopping. There is the threat of flash flood with all streams, so go on a nice sunny day.
But its worth it to go at least once and see for yourself! One person’s misery could be your heaven. That’s my take on hiking. Get out there and good luck!