Most of South Kalimantan's population was Muslim in June 2021.

The Directorate General of Population and Civil Registration (Dukcapil) of the Ministry of Home Affairs (Kemendagri) recorded that the population of South Kalimantan was 4.1 million in June 2021. Of this number, 3.98 million people, or 97.02% of South Kalimantan's population, are Muslim.

South Kalimantan's Christian population was recorded at 54,580 (1.33%). 22,260 people (0.54%) in the province are Catholic.

Furthermore, 23,820 people (0.58%) of South Kalimantan's population are Hindu. 12,290 people (0.3%) are Buddhist.

The number of people in South Kalimantan who practice Confucianism is 206 (0.01%). Meanwhile, 9,080 people (0.22%) adhere to indigenous beliefs.

Based on gender, 2.08 million (50.58%) of the population of Bumi Lambung Mangkurat are male. Meanwhile, 2.03 million (49.42%) are female.

Furthermore, 1.98 million people (48.15%) in South Kalimantan are married, 1.87 million (45.63%) are unmarried, 171,110 (4.17%) are widowed, and 84,100 (2.05%) are divorced.

South Kalimantan is one of the provinces on Borneo Island, with an area of 38,744 square kilometers and a population density of 106 people per square kilometer. Administratively, South Kalimantan is divided into 11 regencies and 2 cities, comprising 153 districts, 1,864 villages, and 144 urban villages.