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Fern Grotto

4.4$· Inexpensive

Discover Kauai's lush tropical lava cave along the scenic Wailua River

Located within Wailua River State Park on Kauai, Fern Grotto is a natural lava rock cavern draped in lush ferns and tropical foliage. Accessible only by water, visitors typically arrive via a scenic riverboat cruise or kayak along the Wailua River, followed by a short paved walk from the dock. An observation deck provides views into the sheltered cave, which is celebrated for its natural acoustics and tranquil rainforest environment.

Quick tip: Book a riverboat tour in advance or rent a kayak, and wear comfortable walking shoes for the paved path leading to the viewing deck.

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