East Kalimantan (Indonesian: ) is a province of Indonesia. Its territory comprises the eastern portion of Borneo/Kalimantan. It had a population of about 3.03 million at the 2010 census (within the present boundary), and 3.766 million at the 2020 census; the official estimate as at mid 2024 was 4,092,984. Its capital is the city of Samarinda, the most populous city on the entire island of Borneo.
East Kalimantan has a total area of 127,346.92 square kilometres (49,168.92 sq mi) and is the third least densely populated province in Kalimantan (after North Kalimantan and Central Kalimantan). The majority of the region shares a maritime border to the east with West Sulawesi and Central Sulawesi; its Cape Mangkalihat separates the Makassar Strait from the Celebes Sea. Its former northernmost region was split off on 25 October 2012 and is now the separate province of North Kalimantan; meanwhile it still shares land border to the west with West Kalimantan and Central Kalimantan; to its south, East Kalimantan borders South Kalimantan. The province bordered Sabah, Malaysia before the creation of North Kalimantan, and still has a short border with Sarawak, Malaysia through Mahakam Ulu Regency.