Kiwai Island is the largest island in the Fly River delta, Papua New Guinea. It is 59 km long along the northwest-southeast axis from Wamimuba Point in the northwest to the village of Saguane (Sanguane) in the south, and up to 9 km wide, with an average width of 5.6 km. Its area is 359 km². Neighboring Purutu and Wabuda Islands to the north and northeast are also among the three largest islands in the Fly River delta.