Maunawili Falls is a popular hike for windward-side residents of O'ahu, and it ends at a pool with fresh rainwater flowing down the black volcanic rock. The jungle foliage hangs down from above, while vines, ferns, and flowers line every square inch of the terrain. Native song birds give you the soundtrack of the islands as you make your way along the trail. Giant banyan trees loom overhead along with the iconic Ko'olau Mountains above them. You dip in and out of thick foliage, and there are large open breaks to show off the sweeping mountain views. The trail is not very long, so people of all ages join along. Hawaiian birds are some of the most beautiful in America, so bring a pair of binoculars or a telephoto lens if possible. Along with the birds you can find mountain apple, bird-of-paradise, giant ferns, mountain orchid, ʻōhiʻa lehua, and countless other plant species both native and introduced.
There is a swimming hole at the base of the falls, and many people climb up the rocks to jump into the pools. Helicopter rescues from people slipping occur more than you might think. Crayfish that swim in these rivers are pretty unique and cool animals, so keep an eye out and you can cook them up on an overnight camping trip. Rains are pretty much a constant possibility in east O'ahu, so expect mud and slippery conditions and wear shoes that you don't mind getting stained with red dirt. The trailhead is in a neighborhood, so please be respectful.