Nunukan is a regency of East Kalimantan in Indonesia. Nunukan is also the name of an island within this regency. It has an area of 226 square kilometers. Nunukan borders with the Malaysian state of Sabah to the north, and Bulungan Regency and Malinau Regency to the south. Nunukan town, the capital of the regency, is located on Nunukan Island. It is a major port for ferry crossings to Tawau in Sabah state, Malaysia.