A national census, that includes religion, is conducted every ten years. Results are broken down into Buddhism, Protestantism, Catholicism, other religion, and no religious affiliation. While there is some fluctuation from one decade to another, the results typically don't move much more than a few percentage points in any direction. Some religious census data exists from 1950, 1960, and 1970 but it appears the data was incomplete. The first survey with complete data was conducted in 1985.

No religious affiliation is the largest group and has gone from a low of 46% in 1995 to a high of 57% in 1985 and a nearly identical 56.1% in 2015. The largest religion followed in South Korea has tended to be Buddhism, with 20% or 23% in most surveys except in 2015 where a lower 15.5% was recorded. Protestantism is usually 3 to 5 percentage points lower ranging from 16% to 20%. In 2015, it passed Buddhism by roughly 4 percentage points. Catholicism is usually seen in single digit numbers of 5%, 7%, and 7.9% in 1985, 1995, and 2015, respectively and was recorded at 11% in 2005. The "other" religion category was highest in 1985 at 2%, followed by 1% in the next two surveys, and 0.8% in 2015.

There has been some debate on the validity of the results as survey methodology changed, going from a whole survey of the entire population in 2005 to an internet-based survey with a 20% sampling in 2015. The census in 2015 is also the only instance in which fractions of percentages appear.

The contents below will give a brief overview of some of the religions practiced in Korea, their historical context, and other useful information.

Shamanism

Known as Muism (무교, 巫敎, mugyo) or Sinism (신교, 神敎, singyo) this religion native to Korea centers around polytheism and animism. Shaman can be either male or female who work to resolve conflict between the spiritual world and the human world through rituals. Rituals (굿, gut) involve a shaman wearing brightly colored clothes and can include songs, dances, and prayers and varies region to region. Many people converted to Buddhism when it was introduced in the 4th century but Shamanism still remained present in the country. The religion was targeted at the end of the Joseon dynasty and during the 1970s and 1980s which resulted in many sites being destroyed. The decades following have seen a resurgence but it remains a minority.

Buddhism

Known in the Korean language as Bulgyo (불교, 佛敎), Buddhism entered Korea in the year 372, which was during the period of the Three Kingdoms, aka Baekje, Silla, and Goguryeo. This was the primary religion and significant cultural influence in the kingdoms of Silla and Goryeo. After the start of the Joseon dynasty in 1392, Buddhism not only lost their dominate presence but underwent centuries of suppression as Korean Confucianism became the state ideology and religion in Joseon. Buddhism is more prevalent in Jeju Island and in areas to the east, specifically the Yeongnam region and Gangwon Province. The Jogye Order is the representative order and traces back more than a century. Buddha's birthday is a national holiday and there is a related annual lotus lantern festival and parade in Jonggak by the head of Cheonggyecheon Stream in Seoul. For details about Korean Buddhist temples and see a list of locations across the peninsula, see this related Wikipedia page or see this other Wikipedia page for a list of Buddhist temples in Seoul.

In preparation of international visitors coming to Korea for the 2002 FIFA World Cup, the Jogye Order of Korean Buddhism started their Templestay program. They have an information center across the street from Jogyesa Temple in Seoul and a bilingual website for information and booking. Programs, length of stays, and prices differ temple to temple. The Seoul Metropolitan Government has an overview page in English.

Confucianism

Along with Buddhism, Confucianism was brought to Korea via China and then developed into Korean Confucianism (한국의 유교, 韓國의 儒敎, Hangukui Yugyo) in the Goryeo kingdom. The religion became the state religion under Joseon. It later moved into other aspects of Korean society and is still fundamental in contemporary life as seen in morality, social hierarchical relationships, and is the foundation for a substantial part of the legal system. Due to this deep connection to modern life and culture, overseas media sometimes attributes cultural differences or specific elements of historical events to Confucianism, whether true or not.

Catholicism

Encountering Roman Catholicism in China during the late Joseon Dynasty, Korean Confusion scholars brought information on the religion back to their home country. The term for Catholicism and its followers in the Korean language is a phonetic usage of the term Catholic (가톨릭, gatollik). The first converts came about from a Korean diplomat returning from Beijing in 1603 who brought back theological books from an Italian Jesuit missionary to China. The religion was outlawed in 1758 and allowed again in 1785 but underwent intense persecution in 1866 leading to thousands of deaths. From 1884, the country reopened which allowed Catholicism more access to the nation. The religion has recovered somewhat since the persecution, but in all of the national censuses it remains a single digital percentage number.

The most well-known cathedral in Korea is the Myeongdong Cathedral in Seoul. The Jeondong Cathedral in Jeonju is well known for the building and the martyrdom that occurred there. Our Lady of Lourdes Cathedral in Daegu is also well known and was visited by Pope John Paul II. Pope Francis also visited South Korea in August 2014 for a four-day visit.

Protestantism

In 1884, the nation became more open to outside nations, leading to the founding of the first domestic Protestant church and medical missionary Horace Newton Allen entering the country. The work of Allen and other medical missionaries, including Horace Underwood, resulted in the opening of Severance Hospital, now a part of Yonsei University. These days, roughly 16% to 20% of the population are Protestant. Known as 개신교 (改新敎, gaesingyo), the Korean term for Protestantism is not a loanword.

Chungdong First Methodist Church in Seoul is Korea’s first Protestant church. Yoido Full Gospel Church is sometimes cited as having the largest congregation in the world. The largest congregation was said to previously be at Youngnak Presbyterian Church, which was founded by refugees during the Korean War.

Islam

Muslim merchants first interacted with the Silla kingdom in the late 7th century. Korean records show Muslims settling on the peninsula in the 9th century with trade relations continuing partway through the 15th century. There is evidence of Hui people from China living in Goryeo and Muslims coming to Korea via Mongolian armies. A 13th century song referencing a Turkish bakery has survived to this day as have other documents from the Goryeo kingdom mentioning Muslims living in Korea at that time. Taken from the Persians, the technique to distill arak was transferred to Korea during the Mongolian invasions (1231-1259) which resulted in modern day soju. Muslim scientists also brought astronomical instruments, mathematical tools, and new calendars which became the official calendars of the late Goryeo kingdom. In 1427, King Sejong declared the “huihui” were to no longer get government stipends and had to integrate into local culture, which included clothing and the closure of their place of worship. This is the last mention of Muslims in that dynasty, in part because Korea soon after became the "hermit kingdom" which stopped international trade. A few interactions occurred in following centuries, but it was minimal until Turkey sent troops to fight in the Korean War. Their humanitarian work both during and after the war also provided ministry opportunities resulting in enough followers that the Korea Muslim Society was founded in 1955. Renamed the Korea Muslim Federation in 1967, they received land from the Korean government and financial support from Muslim countries in order to build a mosque in Itaewon, Seoul.

Islam is known as 이슬람교 (이슬람敎, Iseullamgyo) or 회교 (回敎, Hoegyo) and the Korea Muslim Federation has estimated 100,000 followers of Islam live in Korea, with 70% to 80% of those being international residents. The Federation also oversees Halal certification but most of the information on their website is in Korean. Under the Ministry of Culture and Tourism, the Korean Tourism Organization has an informative overview page on Muslim-friendly restaurant categories, a page on Muslim-friendly restaurants, and several restaurant guides and tourist map in eBook format. Since 2017, the Korean Tourism Organization also hosts the annual Halal Restaurant Week Korea (YouTube channel) for multiple months. The site includes coupons, events, a searchable list of restaurants, mosques, and prayer rooms. Since 2004, the Ministry of Foreign Affairs has annually hosted an Iftar dinner.

The first and most well-known mosque in Korea is the Seoul Central Mosque located on a hill in Itaewon. Despite the elevated location, the mosque can be difficult to find as other buildings block visibility from street level. Mosques can also be found in Busan, Gwangju, Suwon, Daejeon, and Daegu, among others.

Hinduism

Known as Hindugyo (힌두교, 힌두敎) in Korean, Hinduism is primarily practiced in the Indian and Nepali communities. As yoga has grown in popularity, Koreans have gradually had more exposure to Hinduism, but this remains minimal. The temple Sri Radha Shyamasundar Mandir is located in Haebangchon just west of Itaewon and south of Namsan Tower in Seoul. Also located in Seoul, the Himalayan Meditation and Yoga Sadhana Mandir is in Seocho District and is an affiliate center of Association of Himalayan Yoga Meditation Societies. Sri Sri Radha Krishna temple is located north in Seoul in the city of Uijeongbu, Gyeonggi Province.

Judaism

The first real presence of Jews in Korea came as soldiers fighting in the Korean War. The largest Jewish community is in Seoul and a sizable amount continue to be military personnel and their families. As there were no synagogues in the peninsula, accessing Shabbat meals was only via the Yongsan Army Base until Chabad House opened in 2008 (website). Their website also links to a store with Kosher products. The first mikveh opened near the Chabad House and Grand Hyatt Seoul in 2019. There are an estimated 1,000 Jews living in South Korea, most of them are international residents from North America who stay for one to two years (reference) and primarily reside in Seoul. Known as Yutaegyo (유태교, 猶太敎), Koreans know little about Judaism as there are few interactions.

Related Links

For additional information on the topic of religion in Korea, you might want to check the Wikipedia page Religion in South Korea or this page on the government website Korean Culture and Information Service, aka Korea.net.