Beholding the Fern Grotto in Hawaii Is Like Looking Into Another World

One of the most beloved attractions in Hawaii, the Fern Grotto has officially been declared one of The Gemmies in the United States by our team of local travel experts. The 2025 Gemmies are a collection of destinations that are a true representation of their state. To experience these gems is to know the heartbeat of their American locations and we think they are all worthy of a visit.

Kauai's Wailua River is a magical place in a state that often seems like it's nothing but magic. It's the largest and only navigable river in Hawaii, and a trip up the river is an excursion that feels closer to a carefully engineered theme park ride than a float along a natural wonder. As beautiful as the river, itself, may be, it's the sights you'll encounter along the way that create the sense of magical realism. A pair of spectacular cascades - some of the most beloved waterfalls in Hawaii - usher the river along to its destined meeting with the Pacific Ocean, and one of Kauai's most popular attractions, accessible only by boat, lies near the end of the river's lower stretch: the Fern Grotto.

Your portal into this mystic place is Wailua River State Park, which you'll find on the windward side of Kauai, just north of its seat of Lihue, and near the community of Wailua. Unlike many of the Aloha State's parks, there is no fee to enter Wailua River State Park for nonresidents, however the only way to see the Fern Grotto is by by boat. So, you'll either need to rent or bring your own kayak or pay to take a boat excursion from a concession near the mouth to a spot just upstream of where the North and South Forks of the river meet.

A trail from a dock on the river bank leads visitors to the Fern Grotto part of the park. The grotto is a natural cave in the porous lava rock through which water has seeped. Hanging ferns managed to take hold in the rock and, today, give the grotto its distinctive, fantastical appearance. It has long been a sacred place for Native Hawaiians.

Prior to 2006, visitors could venture into the grotto, but a series of deluges caused a rock fall, and rendered the cave unstable. The grotto is still beautiful, but today, you have to enjoy its lush vegetation it from an observation deck, and entry into the cave is forbidden. But it's still a sight to behold.

You can book your excursion and tour of the Fern Grotto on the Wailua River in advance through our friends at Viator. And since you're in the area, you will definitely not want to miss out on the incredible natural wonder that is Waimea Canyon State Park. Have you visited this incredible natural wonder in Hawaii? What are some other places in the Aloha State that are as amazing as the Fern Grotto? We'd love to hear all about them!