Batam is the largest city in the province of Riau Islands, Indonesia. The city administrative area covers three main islands of Batam, Rempang, and Galang, as well as Bulang to the west and several small islands. Batam Island is the core urban and industrial zone, while both Rempang Island and Galang Island maintain their rural character and low-density population; they are connected to Batam Island by short bridges. Bulang Island and the islands to its north forming Belakang Padang District lie to the west of Batam Island but are also administratively within the city. Batam is an industrial boomtown, an emerging transport hub, and part of a free trade zone in the Indonesia–Malaysia–Singapore Growth Triangle, located 20 km (12 mi) off Singapore's south coast.

Christianity is Indonesia's second-largest religion, after Islam. Indonesia also has the second-largest Christian population in Southeast Asia after the Philippines, the largest Protestant population in Southeast Asia, and the third-largest Christian population in Asia after the Philippines and China, followed by India. Indonesia also has the second-largest Christian population in the Muslim world, after Nigeria, followed by Egypt. Indonesia's 29.1 million Christians constituted 10.49% of the country's population in 2022, with 7.43% Protestant and 3.06% Catholic. Some provinces in Indonesia are majority Christian. In Indonesia, the word Kristen refers to Protestantism, while Catholicism is referred to as Katolik. In the 21st century the rate of growth and spread of Christianity has increased, especially among the Chinese minority.