The roughly 16-acre Wailuku River State Park provides lush, dazzling scenery right on the outskirts of Hilo. Multiple gorgeous waterfalls and some impressive cascades make this a very popular destination for sightseeing.
The Wailuku is the longest and largest river in the Hawaiian Islands, running some 28 miles from its headwaters high on the eastern flank of Mauna Kea. It churns along eastward to empty into the Pacific at Hilo Bay. Not far above its mouth, Wailuku River State Park shows off some of this beautiful stream’s eye-popping whitewater.
The state park is open daily and free to enter. You’ll find restrooms here as well as a small trail network and scenic overlooks. The park’s split between two separate sections: the Boiling Pots, accessed via Peepee Falls Drive, and Rainbow Falls, reached via Rainbow Drive.
The Boiling Pots, easily viewed from an observation area, mark a remarkable stretch of cascades and pools flanked by hexagonal basalt outcrops. The name arises from the fact that in heavy flow especially, the river seems to boil through this turbulent reach. Peepee Falls, a handsome and decently tall plunge, lies above the Boiling Pots.
The best-known feature of Wailuku River State Park, though, is Rainbow Falls–aka Waianuenue (“rainbow water”). This 80-foot waterfall, which often manifests as twin streamers, drops over a burly lava ledge into a plunge pool. The ledge tops a cave easily seen behind the falls. Legend has it that this waterfall cave served as home for Hina, the goddess mother of the mythic Hawaiian hero Maui.
Edged by luxuriant tropical forest, Waianuenue is a beautiful and stirring sight anytime. In the middle of a sunny morning, though–about 10 AM or so–it lives up to its name. That’s when perfectly angled sunlight often forms rainbows in the waterfall mist. The rainbows of Rainbow Falls are an unforgettable sight indeed, and the sort of thing professional photographers and amateur shutterbugs alike dream about.
A short trail near Rainbow Falls leads to an impressively proportioned banyan tree–another highlight of the vicinity.
The Wailuku River—which offers Class 5 whitewater in sections that is coveted by experienced kayakers—does see some swimming, diving, and tubing, including in the park’s pools. But this is a notoriously dangerous current, too. Besides the sharp basalt and underwater passages, the Wailuku is prone to flash-flooding, a tendency suggested by the translation of its name: “river of destruction.” Such floods can arise with little warning and super-charge the Wailuku’s flow. Numerous deaths have occurred in the Wailuku River. Exercise plenty of caution here, even if you see people wading, swimming, or cliff-jumping.
From the ethereal rainbows of Waianuenue’s mists to the roar of the Boiling Pots, Wailuku River State Park packs quite the scenic punch just a hop, skip, and a jump from the heart of Hilo.
More waterfalls may be seen along the Wailuku upriver from the park, including Waiale Falls not far above the Boiling Pots.