This was definitely the hardest trail we did on our trip, but the views were spectacular. The trail is a continuous hill, with some rocks. Bring a lot of water. We brought 2L each, and it wasn't enough. We had 4 hours to complete this hike, and it wasn't enough. We had to turn around about 3/4 of the way up. I'd allow 6 hours to do the whole out and back.
Spectacular hike with breathtaking views of the mountain and ocean below. I started at 7:30 am and was happy I did - very little shade so bring lots of water. The ascent was much easier than the descent on account of the consistently changing rocky surfaces. I wore minimalist trail running shoes and recommend something that offers a bit more stability and cushion for the descent. If you go early you'll likely see several whale pods (3 in my case). If you're staying in Lahaina this is a must-do!
Great trail with beautiful views, but don't take it if there are gale warnings! Friend and I did it on a gale warning day and we had to stop about a quarter of the way after we both almost got blown off the rocks within 5 minutes of each other.
Started on the West side, only went up to the windmills, but a great day hike. Lots of field mice on the trail. It's super windy so you won't feel the sun, but it's still going to burn you (I speak from experience). I concur with some reviewers below, the trailhead is a bit hard to find. I was so distracted by the views of the shore that I walked right by it. You'll start on the old highway, but pretty soon after that there will be a trail on your left that goes up the mountain. There are arrows painted on the ground, but somehow I completely missed it. If you start to see the chain link fences on the ground to prevent rock slides, you've missed the trail.
We took the trail from the Maalaea side, headed up to the windmills (just past the 2.5 mile mark) and got some fantastic views of the valley and ocean on both sides. The first mile or so past the trailhead was very steep, but then it got a little better and less exhausting. The full 10 miles would have been way too much for us given the elevation gain, but it worked great as an out-and-back to the halfway point, and took us just around 2.5 hours total. All in all a very enjoyable hike!