The Reunion hotspot is a volcanic hotspot which presently lies under the Island of Réunion in the Indian Ocean. The hot spot is believed to have been active for over 65 million years. A huge eruption of this hot spot 65 million years ago (MYA) is thought to have laid down the Deccan Traps, a vast bed of basalt lava that covers part of central India, and opened a rift which separated India from the Seychelles plateau. The Deccan Traps eruption coincided with the extinction of the dinosaurs, and there is considerable speculation that the two events were related. As the Indian plate drifted north, the hot spot continued to punch through the plate, creating a string of volcanic islands and undersea plateaus. The Laccadive Islands, the Maldives, and the Chagos Archipelago are atolls resting on former volcanoes created 60-45 MYA that subsequently submerged below sea level. About 45 MYA the mid-ocean rift crossed over the hot spot, and the hot spot passed under the African Plate.

The hotspot appears to have been relatively quiet from 45-10 MYA, when activity resumed, creating the Mascarene Islands, which include Mauritius, Réunion, and Rodrigues. Mauritius and Rodrigues ridge were created 8-10 MYA, and Rodrigues and Réunion islands in the last two million years. Piton de la Fournaise, a shield volcano on the southeastern corner of Réunion, is one of the most active volcanoes in the world, erupting last on August 13, 2004.