The Karimata Strait is the wide strait that connects the South China Sea to the Java Sea, between the islands of Sumatra and Borneo in Indonesia.

The strait is about 150 km wide, as measured to the island of Belitung, which is the end of a chain of islands starting with Pulau Bangka off Sumatra's east shore. There is also an eponymous small group of islands in the middle of the strait.