78.3% of the Riau Islands population was Muslim in June 2021.

Islam is the majority religion in the Riau Islands Province. Based on data from the Directorate General of Population and Civil Registration (Dukcapil) of the Ministry of Home Affairs, the number of residents in the province who practice Islam was 1.61 million in June 2021. This number accounts for 78.3% of the total population of 2.06 million in June 2021.

Meanwhile, 244,690 people, or 11.91% of the Riau Islands population, are Christian. There are also 145,910 people, or 7.1% of the population in the province with Tanjungpinang as its capital city, who practice Buddhism.

There are 50,990 people, or 2.48% of the Riau Islands population, who are Catholic. There are also 3,260 people, or 0.16% of the province's population, who practice Confucianism. 913 people, or 0.04% of the Riau Islands population, practice Hinduism. 300 people, or 0.01% of the province's population, adhere to indigenous beliefs.

By gender, 1.05 million people, or 50.92% of the Riau Islands population, are male. Then, 1.01 million people, or 49.08% of the province's population, are female.

Based on marital status, 1.07 million people, or 51.82% of the Riau Islands population, are unmarried. 912,420 people, or 44.39% of the province's population, are married. There are 28,510 people, or 1.39% of the Riau Islands population, who are divorced, and 49,190 people, or 2.39%, who are widowed.

The Riau Islands is a province formed from the Riau Province, with an area of 8,201 square kilometers (km) and a population density of 251 people/km². Administratively, the Riau Islands are divided into 5 regencies and 2 cities, comprising 75 districts with 275 villages and 142 urban villages.