Hiking Papali Ridge to the Castle Trail on Oʻahu, Hawaiʻi
Distance: 9.3 miles / 15.0 km
The Castle Trail is one of the most beautiful, but also one more advanced hikes on Oʻahu.
For this reason, the Castle Trail should not be considered lightly, even if you have a lot of Hawaiʻi hiking experience. I say this because completing the true Castle Trail from Maʻakua to Punaluʻu becomes incredibly challenging to navigate once on the Punaluʻu side of the trail.
Furthermore, the distance posted above will only increase if you do any exploring once at the Kaluanui Stream, which is one of the best things to do on this long all-day adventure!
Papali Ridge Trailhead Parking
Parking for the Papali Ridge Trail is located on on Honomū St in Hauʻula, the same street parking as Maʻakua Ridge and the Hauʻula Loop Trail.
That being said, be sure to plan a ride, stage a car in Punaluʻu, or bring money for the bus because the Castle Trail should only be treated as a one-way hike.
Google Maps Directions: Papali Ridge Trailhead
Hiking the Castle Trail
The Castle Trail begins at the end of Hauʻula Homestead/ Maʻakua Road, which is marked by a Nā Ala Hele trail sign for both the Hauʻula Loop and Maʻakua Ridge Trail.
That being said, don’t forget to pack a headlamp because finishing after sunset is just as likely as not, based on how slow the hike down into Punaluʻu can be.
Shortly after the sign in the photo above, you will pass two sets of gates before reaching the true trailhead just off the road.
Maʻakua Ridge Trailhead
At the joint Maʻakua Ridge-Hauʻula Loop Trailhead, go left to begin the Maʻakua Ridge Trail.
After the left turn, stay on the Maʻakua Ridge Trail for about 1.5 miles (2.4 km) until the Papali Ridge junction on the north side of the loop.
Maʻakua Stream
Shortly after leaving Maʻakua Road, the trail will come to a large stream crossing.
The Maʻakua Stream will almost always be dry unless it has been raining heavily further up in the mountains.
Look across the stream to the right to find the trail that continues on.
After the Maʻakua Stream crossing, the trail will climb a handful of switchbacks up to the Maʻakua Loop.
Maʻakua Ridge Bench
It’s no secret that this bench is the best and only viewpoint on the Maʻakua Ridge Trail.
That being said, the rest of the trail is more or less a walk in the woods, meaning that most people choose to turn around after reaching this point in the trail.
Maʻakua Loop
Behind the bench is the split for the Maʻakua Loop.
Go right to continue on the fastest route toward Papali Ridge.
Maʻakua-Papali Ridge Junction
At about 1.5 miles (2.4 km), the Maʻakua Ridge Trail will split, which is the start of the Papali Ridge Trail.
At this split, go right up Papali Ridge to continue toward the Castle Trail.
Papali Ridge
For the remaining sections, I highly recommend good hiking pants because the overgrowth will remain fairly constant for the rest of the hike.
The pants below are my recommendations that hold up the best with the overgrowth here in Hawaiʻi, but with any hiking pants that need to be durable, make sure that they are at or near 100% nylon. This is really the most important factor!
Essentially, the Papali Ridge Trail is a bit of a rollercoaster until one of the best break spots at about 2.8 miles (4.5 km).
Additionally, this small landslide in the photo below may get worse and worse over time, as more sections continue to fall.
The grassy spot is a nice sign that the steepest elevation changes are behind you, meaning the rest of Papali Ridge to the Castle junction is much more mild in comparison.
Once at the ungulate-exclusion fence and the Kaluanui sign, the Papali Ridge gets much easier to walk until the Castle junction.
However, this easy section doesn’t last for long.
Castle Trail
Shortly after coming off of the little overlook in the photo above, the gate for the Castle Trail will be located right at the bottom of the hill.
As bad as these photos might make the overgrowth look, I was very impressed by how fast we moved through this section down to the Kaluanui Stream.
That being said, this fenced-in management unit is a critical habitat for conservation efforts, protecting a number of native Hawaiian species. Therefore, I ask that you please do your best to minimize your impact and respect the conservation efforts underway within the management unit.
After 0.8 miles (1.3 km) from the Papali Ridge Trail, the Castle Trail meets the Kaluanui Stream.
Again, please don’t do anything that would damage or vandalize this important conservation area for the crews that utilize this shelter.
At the very beginning of the grassy open area in the photo above, the exit trail can be found on the left-hand side as you walk in. Both trails in and out of Kaluanui were neither more or less overgrown than the other.
However, the exit trail only ascends about a 200 ft. (61 m) out of Kaluanui compared to a 400 ft. (122 m) descent from Papali Ridge.
As if hikers are going to be coming from this direction, I thought this was kind of an odd place to put a sign.
Please be sure to close the ungulate-exclusion fence after passing through.
Punuluʻu Valley
Once through the famous Castle Notch, you’ll get one of the best and most expansive views you can find on Oʻahu, granted that you’re hiking on a clear day!
However, I say, enjoy it because it won’t last long!
The traverse to the ridge down continues straight from the notch.
After less than a quarter mile on this traverse, turn right down the most prominent ridge into Punaluʻu Valley.
That being said, don’t expect any kind of descent trail, like the rest of the hike up to this point, and if my photos look like there is a path to follow, it’s because I wasn’t leading, as two people before me trampled down the overgrowth.
Multiple times on the ridge, you will come across what look like descent side trails, like the spot in the photos below.
I need to learn more about the history of these trails, but they look like they more or less contour the valley, and they never appeared to be a good enough path to follow, which is why I suspect the one in the photo below was roped off.
Nevertheless, my best advice is to stay directly on the ridgeline of the biggest, most prominent ridge down into Punaluʻu Valley.
Even if you see a side trail that looks better or the most prominent ridge doesn’t look like the best way, trust me, you don’t want to end up like we did.
This photo below was climbing down the main ridge to another trail that looked like it was contouring/ traversing the side of the valley. It may have been the most prominent looking one, but it never seemed like the best path that we should trust, as if we made a left.
Therefore, we kept following the the ridge.
Somewhere in this area of these last two ridge photos is where we went wrong, and it’s exactly why I say, stay on the main ridge! However, once we made it to the area in the photo below, there was almost no doubt that we were going to drop down into the gulch on the right. It was as if we were too far along to turn around and figure out a better path.
Nevertheless, when we made the decision to drop down into the stream, we started making our way down to the right. The final down climb was about 50 ft. (15 m), and it definitely had its moments!
However, when we were in the process of figuring out the near-vertical down climb, I think I said, “WTF! There’s a rope! How are we not the first humans in history to ever step foot here?”
Somehow, someway, somebody else got just as off-track as we did and tied a rope to make the final descent. Since we didn’t know how long the rope had been there, we chose not to use it. However, Mark, the first one to climb down, tested his weight on it once in the gulch, and it held! Still, I didn’t rely on it.
One by one, we all made it down, and not a moment too soon because the mosquitoes were horrible!
After meandering on either side of the stream for a while, we finally saw our first signs of life.
Before even going on the hike, I knew that the end of the trail from the notch to the valley floor was going to be a guessing game, so eventually, I was confident we’d hit a road to walk out of there.
Just before the road, I noticed where the ridge down terminated next to where we walked out through the stream.
That’s why I kept saying, stay on the main ridge, so that you can ideally walk down into the valley on the best gradual slope you can find and avoid the climbing that we had to do.
I guess this is one reason why the Castle Trail is a one-direction hike from Papali Ridge.
You will be turned around if you try to enter through Punaluʻu, and I’d say your chances of finding the right route up are slim to none compared to making down into the valley from the other direction.
Turn right to exit on Punaluʻu Valley Road.
We staged a car to get back to the Maʻakua-Hauʻula Loop Trailhead.
Alternatively, the bus could be a good option.
Native Plants on the Castle Trail
The upper elevations of Papali Ridge and the Castle Trail are some of my favorite places on Oʻahu to look for native Hawaiian plants.
I think my favorite find on this day was Hulumoa, also called the native Hawaiian Mistletoe, but be on the lookout for ʻAhakea, Kōpiko, ʻŌhiʻa lehua, ʻŌhiʻa ha, various ʻŌhelo species, Kāwaʻu, Kokiʻo Keʻokeʻo, and ʻAkolea, to really only name a few.
If you would like to know more about these and tons of other native Hawaiian plants from across the islands, I encourage you to check out my separate post linked below.
Read My Separate Post: Native Hawaiian Plant Guide
