Sebuku (old spelling Seboekoe) is a 275-square-kilometre (106 sq mi) island south-east of Borneo and administratively part of South Kalimantan, Indonesia.

Sebuku is located to the south-east of Borneo, approximately 5 kilometres (3.1 mi) from Laut Island.

[2] Large deposits of coal, dating from the Eocene, have been found in Sebuku's south-west region; the main deposit forms a syncline which trends from north to south.

[1] Sebuku is home to roughly 4,900 people, with a total population density of 17.8 inhabitants per square kilometre (46/sq mi).

[1] Although the Dutch originally discovered at least 25 coal deposits on Sebuku, after realizing that the island may not survive mining they cancelled their plans.