Portion of the western Pacific Ocean between the islands of Java and Borneo. It is bordered by Borneo (Kalimantan) on the north, the southern end of Makassar Strait on the northeast, Celebes and the Flores and Bali seas on the east, Java on the south, the Sunda Straits to the Indian Ocean on the southwest, Sumatra on the west, and the islands of Bangka and Belitung (bordering the South China Sea) on the northwest. The sea measures about 900 miles (1,450 km) east-west by 260 miles (420 km) north-south and occupies a total surface area of 167,000 square miles (433,000 square km).