Saunders Island is a crescent-shaped island lying between Candlemas Island and Montagu Island in the South Sandwich Islands, a British Overseas Territory in the southern Atlantic Ocean.
The 8.5 by 5 kilometres (5.3 mi × 3.1 mi) long Saunders is a volcanic island composed of an active stratovolcano, 990-metre (3,248 ft) Mount Michael, and a cluster of pyroclastic cones on the southeastern side. Mount Michael has a lava lake in its summit crater, which is fumarolically active, and there is widespread evidence of recent eruptions across the island.