The Wailua River is a river on the island of Kauai in the U.S. state of Hawaii. It begins at the Wai?ale?ale crater and is the only navigable river (by boats larger than kayaks) in the Hawaiian Islands. It is a center of activity for locals and visitors in the form of boat tours to Fern Grotto, kayaking and water skiing. Other points of interest along the river include a bird refuge, Halokila Hawaiian Village, Secret Falls and a pool for rope jumping.