Tumaguin (variously Tamaguin, Tomaquin, or Tumaguin Islet) is a small, uninhabited island in the . Along with nearby Sicogon Island, it is part of Carles, Iloilo.
Tumaguin Island is located due east of Sicogon Island. The island is above sea level. There is a four fathom patch of deep water a little over from the island.
Tumaguin Island is accessible from barangay Buaya in Sicogon by boat, or by foot during low tide.