For a fun kayaking Kauai activity, paddle tandem kayaks along the Hule'ia River and travel deep into the heart of the Kauai island jungle. Then, go Kauai hiking on a 3/4-mile (1.2km) trek up the valley to an enchanting area of waterfalls and swimming holes. On the way back, be picked up in a twin-hulled powered Hawaiian canoe for the return trip!