Onikiniki/Small Waimalu Loop is a trail I learned after joining the Hawaii Trail and Mountain Club. I helped clearing a portion last November with the Trail Maintance Crew at then decided I wanted to take the Pecos River Hikers on this trail. If done in a counter clockwise direction it can be both a Novice or Intermediate hike depending on how big a chunk you choose to hike. The novice hikers can go up Onikiniki as far as they like and then back track to the cars as the beginning of the hike is rather easy first on an old jeep road and then on a nice ridge trail.
As the crow flies the trail is 7.55 miles long (GPS readings). When you add the ups and downs and zigs and zags it could be anywhere from 8 to 9 miles long.
The hike is located above Pearl Ridge between Aiea and Pearl City on the island of O`ahu. To get there take Kaonohi mauka as far as you can and at the top of the ridge turn right onto Onikiniki Place and find a parking place. See below map.