For those who prefer to travel by boat, Wailua Kayak Adventures and Kayak Wailua offer tours that begin with a slow, two-mile paddle down the calm Wailua River, pass an old Hawaiian village along the banks and end in the middle of a tropicalrainforest.
National Geographic Expeditions runs tours throughout the year for the same price, covering natural wonders like Easter Island and the tropical Daintree rainforest in Australia.