The Urauchi is the longest river in Okinawa and the centrepiece of any first trip to Iriomote. Wide, dark and slow, it cuts inland through a tunnel of mangroves and subtropical forest. Tourist boats run upstream from the Urauchi-gawa pier in the morning and afternoon, dropping passengers at a small landing about 8 km in.
From there a marked path leads through the forest to the Mariudo and Kanpire waterfalls — about an hour each way on foot. The walk is humid, muddy in places, and unforgettable. Bring water, mosquito repellent, and shoes that can get wet.