The sea between the Indonesian islands of Java and Borneo is the Java Sea.
The Java Sea is a broad, shallow sea on Indonesia’s Sunda Shelf. Java forms its southern boundary and Borneo, also called Kalimantan in Indonesia, lies to the north. Sumatra is to the west and Sulawesi to the east, placing the sea at the centre of the Indonesian archipelago.
It covers about 320,000 square kilometres and has a mean depth of only 46 metres. Its flat seabed is part of the Sunda Shelf, which was dry land during lower sea levels in the last ice age. Rising seas later drowned that landscape and created the shallow marine basin seen today.
The Java Sea supports fishing, shipping, tourism and offshore petroleum and natural-gas production. It is sometimes classified as part of the western Pacific, although some references associate it with the Indian Ocean. It should not be confused with the Bali, Flores or Banda seas, which border other parts of Indonesia.