Indonesia–Thailand border

Indonesia and Thailand share a common maritime border in the northern part of the Straits of Malacca and the Andaman Sea to the north-east of Indonesia's Sumatera Island and to the west of the western coastline of southern Thailand. The maritime boundary runs between the India-Indonesia-Thailand tripoint in the north, and the Indonesia-Malaysia-Thailand tripoint in the south.

The border was delimited through four agreements, with two involving third parties India and Malaysia as they determined trijunction points with those countries.