The Natuna Sea (Indonesian: Laut Natuna) is an extensive shallow sea located around the Natuna Regency, extending south of the Riau Islands, east of the Lingga Regency and west of Borneo, to the Bangka Belitung Islands.

The islands of the Badas and Tambelan Archipelago are located at its center.

Mostly located within Indonesian territorial waters, it is the southernmost portion of the South China Sea, and geologically part of Sunda Shelf.

[3] The 1986 draft of the IHO's Limits of Oceans and Seas proposed the Natuna Sea, which extends south from the Natuna and Anambas Islands to the Belitung Islands.

[4] In July 2017, Indonesia renamed the northern reaches of its exclusive economic zone in the South China Sea as the "North Natuna Sea", which is located north of the Indonesian Natuna Regency, bordering southern Vietnam's exclusive economic zone.