To grasp the full import of these falls, you have to review the tales of intrigue surrounding the area, wherein ancient gods played and fought, creating these most interesting settings.
The Falls are part of the Wailuku River State Park. Various access points may be found as you drive out of Hilo. From downtown, at Kamehameha Ave, turn on to the one way street, Waianuenue Ave... following it inland past the High School. When the road forks, stay to the right... look for the park sign on your right. Pull into the large parking lot and enjoy the short walking loops... one that could take you around and up to the top of the Falls.
Most folks simply enjoy the lower view... rock wall lined and protected from the raging waters. Well... if it flooded they might rage. On most days you'll enjoy enough flow to create the mist characteristic of producing those Rainbows.
As a side note: where the road forked: that was the beginning of the Saddle Road. The Saddle Road cuts across the middle of the big island, providing access to both Mauna Kea and Mauna Loa... and to the far side of the Island proper. Some local maps still list this route as prohibited for transit of rental cars. In Fact, the road is under massive improvement. It is newly smooth, wide and straight out past the Mauna Kea State Recreation area, the camping area mid island. The far end of the road remains narrow, twisty and lacking shoulders... but the plans are in motion for improving and "fixing" those aspects. Too bad!
These Falls are not really worthy of a dedicated trip; there is no real hiking. But, if you are in the Hilo area you might as well drive out and take in the view. Time it to catch the Saturday or Wednesday Farmers Market in downtown Hilo... better yet, hit the market then carry that great picnic out to the Falls!
This hike is listed as One-Way.
When hiking several trails on a single "hike", log it with a generic name that describes the hike. Then link the trails traveled, check out the example.
WARNING! Hiking and outdoor related sports can be dangerous. Be responsible and prepare for the trip. Study the area you are entering and plan accordingly. Dress for the current and unexpected weather changes. Take plenty of water. Never go alone. Make an itinerary with your plan(s), route(s), destination(s) and expected return time. Give your itinerary to trusted family and/or friends.