Wailua River
"The only river in the state you can actually paddle, and it feels like a secret."
Hawai'i's only navigable river — kayaking to hidden waterfalls, ancient heiau temple sites, and the Fern Grotto's dripping green cavern.
Hawai’i’s rivers are mostly short, steep, and unnavigable — volcanic islands don’t produce the kind of long, lazy waterways you’d paddle for hours. The Wailua is the exception, and it’s the reason Kaua’i’s east side has a kayaking culture that doesn’t exist anywhere else in the state. Lia found the outfitter through a recommendation from our guesthouse host, a woman who insisted, with real conviction, that we not leave the island without doing it.
Paddling Past the Heiau
The lower river winds past a string of ancient heiau — Hawaiian temple sites, some still marked by low stone platforms half-swallowed by jungle. We paddled the main stem for close to two miles, passing Hikinaakala Heiau near the river mouth and, further up, the more secluded sites that require a guide or genuine local knowledge to find at all. The water was flat and the current gentle enough that we mostly just drifted, watching kingfishers work the banks and feeling, more than once, like we’d wandered into a different century.

Secret Falls and the Hike In
We beached the kayaks at a small landing and hiked twenty minutes through mud and root-tangled forest to Uluwehi Falls — better known, accurately, as “Secret Falls” — a wide curtain of water dropping into a swimming pool ringed by volcanic rock. It wasn’t secret in the sense of empty; a dozen other paddlers had made the same trip. It was secret in the sense that nothing about the approach — the highway, the marina, the placid lower river — suggests that something this dramatic is hiding twenty minutes upstream and on foot.

The Fern Grotto, the Easy Way
For those unwilling or unable to kayak, a river barge company runs a short, slightly kitschy cruise up to the Fern Grotto — a natural lava-rock amphitheater draped in hanging ferns that, before a 2018 hurricane, hosted actual wedding ceremonies inside the cave. Storm damage has limited close access since, but the barge ride itself, complete with a ukulele player performing the Hawaiian Wedding Song, is a strange, sincere little piece of old-school Hawai’i tourism that I found myself enjoying more than I expected to.
When to go: Year-round, though water levels and clarity are best from late spring through fall. Book kayak tours in the morning to beat both the afternoon heat and the rain that tends to build over the interior later in the day.
Keep exploring
More from Hawai'i
hawaii Wailuku Town
Maui's unglamorous former county seat, all plantation-era storefronts and a courthouse turned museum, where nobody is selling you anything.
Explore
hawaii Waimanalo
The longest, widest, least photographed white-sand beach on Oahu, in a town that has quietly resisted every wave of development around it.
Explore
hawaii Waimea Canyon
The 'Grand Canyon of the Pacific' — a 3,600-foot-deep red-rock gorge carved by rain on a volcanic island.
Explore
hawaii Waimea Town
The west side plantation town where Captain Cook first stepped onto Hawaiian soil, now a quiet gateway to Waimea Canyon with more history than traffic.
Explore
hawaii Waipi'o Valley
A mile-wide amphitheater of taro fields and wild horses at the bottom of the steepest road in Hawai'i, guarded by cliffs a thousand feet high.
Explore
hawaii Akaka Falls
A 135-meter waterfall reached by an easy loop trail through bamboo and wild orchids on the Big Island's lush Hamakua Coast.
Explore