Andaman Sea, an arm of the Indian Ocean. It is bordered by upper Burma on the north, the Malay Peninsula on the east, Sumatra on the south, and Andaman and Nicobar Islands on the west. The sea is about 850 miles (1,370 km) long, north-south, and up to 420 miles (680 km) wide. Rangoon, Burma, is the leading port. The Irrawaddy, Salween, and Sittang are the chief rivers emptying into the sea.