The Maunawili Falls trail leads through dense lowland rainforest at the foot of the Koolau range to a 6-metre waterfall with a pool deep enough for swimming. The trail is about 5 km return, crosses the Maunawili stream several times — wet feet are guaranteed after rain — and includes a few short rooty climbs.
The trail has been closed for restoration in recent years; check the current status before going. Even when the lower portion is closed, the connector to the longer Maunawili Demonstration Trail offers some of the best windward-Koolau hiking — a 9-mile contour trail across the base of the mountains with continuous views over Kailua and Waimanalo.