Kotabaru Regency

Kotabaru Regency is one of the eleven regencies in the Indonesian province of South Kalimantan. It consists of two parts; the smaller (2,357.29 km²) but more populated part comprises Laut Island ("Sea Island"), the largest island off the coast of Kalimantan (Indonesian Borneo), together with the smaller Sebuku Island off Laut Island's east coast and even smaller islands nearby; the larger (7,122.88 km²) but less populated part consists of districts on the mainland of Kalimantan. The regency as a whole has an area of 9,480.17 km², and had a population of 290,142 at the 2010 Census and 325,622 at the 2020 Census. The official estimate as at mid 2022 was 334,158 (comprising 172,613 males and 161,545 females), of whom 178,660 were in the insular part and 155,498 in the mainland part of the regency. The regency seat is located at the large town of Kotabaru at the northern tip of Laut Island.

It has the second largest GRDP in the province after the city of Banjarmasin, mainly due to its coal industry. It is also the largest regency by land area in the province.