The first principle of Indonesia's philosophical foundation, Pancasila, is "belief in the one and only God". A number of different religions are practiced in the country, and their collective influence on the country's political, economic and cultural life is significant. The Indonesian Constitution guarantees freedom of religion. However, the government only recognizes six official religions (Islam, Protestantism, Catholicism, Hinduism, Buddhism and Confucianism). Indonesian law requires that every Indonesian citizen hold an identity card that identifies that person with one of these six religions, although citizens may be able to leave that section blank. Indonesia does not recognize agnosticism or atheism, and blasphemy is illegal. In the 2010 Indonesian census, 87.18% of Indonesians identified themselves as Muslim (with Sunnis 99%, Shias 0.5%, Ahmadis 0.2%), 6.96% Protestant, 2.91% Catholic, 1.69% Hindu, 0.72% Buddhist, 0.05% Confucianism, 0.13% other, and 0.38% unstated or not asked.
With many different religions practiced in Indonesia, conflicts between followers of different religions arise periodically. Moreover, Indonesia's political leadership has played an important role in the relations between groups, both positively and negatively, promoting mutual respect by affirming Pancasila but also promoting a Transmigration Program, which has caused a number of conflicts in the eastern region of the country.
Historically, immigration from India, China, Portugal, Arabia, and the Netherlands has been a major contributor to the diversity of religion and culture within the country. However, these aspects have changed since some modifications have been made to suit the Indonesian culture.
Prior to the arrival of the Abrahamic faiths of Christianity and Islam, the popular belief systems in the region were thoroughly influenced by Dharmic religious philosophy through Hinduism and Buddhism. These religions were brought to Indonesia around the 2nd and 4th centuries, respectively, when Indian traders arrived on the islands of Sumatra, Java and Sulawesi, bringing their religion. Hinduism of Shaivite traditions started to develop in Java in the fifth century AD. The traders also established Buddhism in Indonesia which developed further in the following century and a number of Hindu and Buddhist influenced kingdoms were established, such as Kutai, Srivijaya, Majapahit, and Sailendra. The world's largest Buddhist monument, Borobudur, was built by the Kingdom of Sailendra and around the same time, the Hindu monument Prambanan was also built. The peak of Hindu-Javanese civilisation was the Majapahit Empire in the fourteenth century, described as a golden age in Indonesian history.
Islam was introduced to Indonesia in the fourteenth century. Coming from Gujarat, India, Islam spread through the west coast of Sumatra and then developed to the east in Java. This period also saw kingdoms established but this time with Muslim influence, namely Demak, Pajang, Mataram and Banten. By the end of the fifteenth century, 20 Islam-based kingdoms had been established, reflecting the domination of Islam in Indonesia.
The Portuguese introduced Catholicism to Indonesia, notably to the island of Flores and to what was to become East Timor. Protestantism was first introduced by the Dutch in the sixteenth century with Calvinist and Lutheran influences. Animist areas in eastern Indonesia, on the other hand, were the main focus Dutch conversion efforts, including Maluku, North Sulawesi, Nusa Tenggara, Papua and Kalimantan. Later, Christianity spread from the coastal ports of Borneo and missionaries arrived among the Torajans on Sulawesi. Parts of Sumatra were also targeted, most notably the Batak people, who are predominantly Protestant today.
Significant changes in religion aspect also happened during the New Order era. Following a purported coup in 1965 officially blamed on the Communist Party of Indonesia, around 1/2 million were killed in an anti-communist purge. Following the incident, the New Order government had tried to suppress the supporters of PKI, by applying a policy that everyone must choose a religion, since PKI supporters were mostly atheists. As a result, every Indonesian citizen was required to carry personal identification cards indicating their religion. The policy resulted in a mass religion conversions, topped by conversions to Protestantism and Catholicism (Christianity). The same situation happened with Indonesians with Chinese ethnicity, who mostly were Confucianists. Because Confucianism was not one of the state recognised religions, many Chinese Indonesians were also converted to Christianity.
The history of Islam in Indonesia is complex and reflects the diversity of Indonesian cultures. There is evidence of Arab Muslim traders entering Indonesia as early as the 8th century. By the 15th century, the spread of the religion accelerated via the missionary work of Maulana Malik Ibrahim (also known as Sunan Gresik, originally from Samarkand) in Sumatra and Java as well as Admiral Zheng He (also known as Cheng Ho, from China) in north Java. Islam in Indonesia is in many cases less meticulously practiced in comparison to Islam in the Middle East region. Majority of Indonesian Muslims practice Sunni Islam of Shafi school of jurisprudence.
After the resignation of Suharto, political parties were again permitted to declare an ideology other than Pancasila. Several Muslim parties formed with Shariah as their ideology and the Crescent Star Party came in 6th place in the Indonesian legislative election, 1999. However, in the Indonesian legislative election, 2009, the Crescent Star Party ranked only 10th, while parties characterized by moderate and tolerant Islamic interpretations had more significant success, such as the Prosperous Justice Party coming in 4th with nearly 8% of total votes cast.
Protestants form a significant minority in some parts of the country. For example, on the island of Sulawesi, 17% of the citizens are Protestants, particularly in Tana Toraja regency in South Sulawesi province and Central Sulawesi. Furthermore, up to 65% of the ethnic Torajan population is Protestant. The Batak from North Sumatra is also one of the major Protestant groups in Indonesia. Christianity was brought by Ludwig Ingwer Nommensen who is known as apostle to the Batak people and started the Huria Kristen Batak Protestant church in Indonesia. Chinese Indonesians are also significant part of the Protestant population, scattered throughout Indonesia with the majority concentrated in major urban areas. In 2000 approximately 35% of ethnic Chinese were Christian, however there is continuous increase among the younger generation. In some parts of the country, entire villages belong to a distinct denomination, such as Adventist, International Church of the Foursquare Gospel, Lutheran, Presbyterian or Salvation Army (Bala Keselamatan) depending on the success of missionary activity. Indonesia has two Protestant-majority provinces, which are Papua and North Sulawesi, with 60% and 64% of the total population consecutively. In Papua, the faith is most widely practiced among the native Papuan population. In North Sulawesi, the Minahasan population centered around Manado converted to Christianity in the nineteenth century. Today most of the population native to North Sulawesi practice some form of Protestantism, while transmigrants from Java and Madura practice Islam. The practitioners mostly live in North Sumatra, West Kalimantan, Central Kalimantan, South Sulawesi, West Sulawesi, Central Sulawesi, North Sulawesi, East Nusa Tenggara, North Maluku, Maluku (province), West Papua (province), Papua (province).
Catholicism arrived in Indonesia during the Portuguese arrival with spice trading. Many Portuguese had the goal of spreading Roman Catholicism in Indonesia, starting with Moluccas (Maluku) in 1534. Between 1546 and 1547, the pioneer Christian missionary, Saint Francis Xavier, visited the islands and baptised several thousand locals.
During the Dutch East Indies (Vereenigde Oost-Indische Compagnie) era, the number of Roman Catholicism practitioners fell significantly, due to VOC policy to ban the religion. Hostility of the Dutch toward Catholicism is due to its history where the Protestant Dutch gained their independence after the Eighty Years War against Catholic Spain's rule. The most significant result was on the island of Flores and East Timor, where VOC concentrated. Moreover, Roman Catholic priests were sent to prisons or punished and replaced by Protestant priests from the Netherlands. One Roman Catholic priest was executed for celebrating Mass in a prison during Jan Pieterszoon Coen's tenure as Governor-General of the Dutch East Indies. After the VOC collapsed and with the legalization of Catholicism in the Netherlands starting around 1800, Dutch Catholic clergy predominated until after Indonesia's independence.
Other than Flores, Central Java also have significant numbers of Catholics. Catholicism started to spread in Central Java when Frans van Lith, a priest from The Netherlands came to Muntilan, Central Java in 1896. Initially, his effort did not produce a satisfying result, until 1904 when four Javanese chiefs from Kalibawang region asked him to give them education in the religion. On 15 December 1904, a group of 178 Javanese were baptised at Semagung, Muntilan, district Magelang, Central Java, near the border of province DI Yogyakarta. In Java, next to Javanese, Catholicism also spread to Chinese Indonesian.
As of 2006, 3% of all Indonesians are Catholics, about half the number of Protestants at 5.7%. The practitioners mostly live in West Kalimantan, Papua (province) and East Nusa Tenggara. The province of East Nusa Tenggara where the island of Flores and West Timor located is notable as the only province in Indonesia where Catholics are majority (about 54.56% of total population).
Hinduism in Indonesia takes on a tone distinct from other parts of the world. For instance, Hinduism in Indonesia, formally referred as Agama Hindu Dharma, never applied the caste system. It also incorporated native Austronesian elements that revered hyangs, deities and spirits of nature and deceased ancestors. The Hindu religious epics, the Mahabharata and the Ramayana, are expressed in uniquely Indonesian wayang puppetry and dance. In many areas on Java, Hinduism and Islam have heavily influenced each other, in part resulting in Abangan and Kejawen traditions.
All practitioners of Agama Hindu Dharma share many common beliefs, mostly the Five Points of Philosophy: the Panca Srada. These include the belief in one Almighty God, belief in the souls and spirits and karma or the belief in the law of reciprocal actions. Rather than belief in cycles of rebirth and reincarnation, Hinduism in Indonesia is concerned more with a myriad of local and ancestral spirits. In addition, the religion focuses more on art and ritual rather than scriptures, laws and beliefs. Balinese Hinduism also holds to the concept of Tri Hita Karana, nurturing and maintaining a harmonious relationship between human and God, human and human, human and nature.
As of 2007, the official number of Hindu practitioners was 10 million, giving Indonesia the fourth largest number of Hindus in the world. This number is disputed by the representative of Hinduism in Indonesia, the Parisada Hindu Dharma. The PHDI gives an estimate of 18 million. Of this number, 93% of the practitioners are located in Bali, the majority of the population of which is Hindu. Besides Bali, Sumatra, Java, Lombok, Kalimantan and Sulawesi also have significant Hindu populations; most are Balinese who migrated to these areas through government sponsored transmigration program or urbanized Balinese attracted to cities in Java, especially the Greater Jakarta area. Central Kalimantan has a 15.8% Hindu population. The Hindu variant of Kalimantan is identified as Hindu Kaharingan, although this native Dayak belief may be more correctly categorized as Animism, rather than Hinduism.
Sikhs are typically registered as Hindus because the Indonesian government does not recognize Sikhism as a religion.
Buddhism is the second oldest religion in Indonesia, arriving around the sixth century. The history of Buddhism in Indonesia is closely related to the history of Hinduism, as a number of empires based on Buddhist culture were established around the same period. Indonesian archipelago has witnessed the rise and fall of powerful Buddhist empires such as Sailendra dynasty, Srivijaya and Mataram Empires. The arrival of Buddhism was started with the trading activity that began in the early of first century on the Silk Road between Indonesia and India. According to some Chinese source, a Chinese traveler monk on his journey to India, witnessed the powerful maritime empire of Srivijaya based on Sumatra. The empire also served as a Buddhist learning center in the region. A number of historical heritage monuments can be found in Indonesia, including the Borobudur Temple in Yogyakarta and statues or prasasti (inscriptions) from the earlier history of Buddhist empires.
Following the downfall of President Sukarno in the mid-1960s, Pancasila was reasserted as the official Indonesian policy on religion to only recognise monotheism . As a result, founder of Perbuddhi (Indonesian Buddhists Organisation), Bhikku Ashin Jinarakkhita, proposed that there was a single supreme deity, Sang Hyang Adi Buddha. He was also backed up with the history behind the Indonesian version of Buddhism in ancient Javanese texts, and the shape of the Borobudur Temple.
According to the 2000 national census, roughly 1% of the total citizens of Indonesia are Buddhists, which takes up about 2 million people. Most Buddhists are concentrated in Jakarta, although other provinces such as Riau, North Sumatra and West Kalimantan also have a significant number of practitioners. However, these totals are likely high, due to the fact that practitioners of Confucianism and Taoism, which are not considered official religions of Indonesia, referred to themselves as Buddhists on the census.
Confucianism originated in China and was brought to Indonesia by Chinese merchants, as early as the 3rd century AD. Unlike other religions, Confucianism evolved more into loose individual practices and belief in the code of conduct, rather than a well-organized community religion with a firm theology -- it was more like a way of life or social movement than a religion. It was not until the early 1900s that Confucianists formed an organization, called Tiong Hoa Hwee Koan (THHK) in Batavia (now Jakarta).
After the independence of Indonesia in 1945, Confucianism in Indonesia was affected by several political conflicts. In 1965, Sukarno issued Presidential Decree No. 1/Pn.Ps/1965, recognizing that six religions are embraced by the Indonesian people, including Confucianism. In 1961, the Association of Khung Chiao Hui Indonesia (PKCHI), a Confucianist organization, had declared that Confucianism is a religion and Confucius is their prophet.
Under the New Order regime of Suharto, anti-China policy became a scapegoat method to gain political support from the masses, especially after the fall of the Indonesian Communist Party, which had allegedly been backed by China. In 1967, Suharto issued controversial Presidential Instruction No. 14/1967, which effectively banned Chinese culture, including documents printed in Chinese, expressions of Chinese belief, Chinese celebrations and festivities, and even Chinese names. However, Suharto knew that the Chinese Indonesian community had a lot of wealth and power even though it consisted of only 3% of the population.
In 1969, Statute No. 5/1969 was passed, restoring the official total of six religions. However, it was not always put into practice. In 1978, the Minister of Home Affairs issued a directive asserting there are only five religions, excluding Confucianism. On 27 January 1979, a presidential cabinet meeting decided that Confucianism is not a religion. Another Minister of Home Affairs directive in 1990 re-iterated the total of five official religions in Indonesia.
Therefore, the status of Confucianism in Indonesia in the New Order regime was never clear. De jure, there were conflicting laws, because the higher law permitted Confucianism, but the lower law did not recognize it. De facto, Confucianists were not recognized by the government and they were forced to become Christians or Buddhists to maintain their citizenship. This practice was applied in many places, including the national registration card, marriage registration, and family registration card. Civics education in Indonesia taught school children that there are only five official religions.
Following the fall of Suharto in 1998, Abdurrahman Wahid was elected as the country's fourth president. Wahid rescinded Presidential Instruction No. 14/1967 and the 1978 Minister of Home Affairs directive. Confucianism once again became officially recognized as a religion in Indonesia. Chinese culture and Chinese-affiliated activities were again permitted. However, after the implementation of Otonomi Daerah (Regional Autonomy), provinces and regencies were permitted to control their own administrative procedures. In 2014, there are again administrative districts that only permit five possible religious affiliations on the national identity card, a restriction that they have programmed into their computer databases.
Kebatinan or Kejawen (Javanese beliefs) or Kepercayaan kepada Tuhan Yang Maha Esa (Believer of One Supreme God) is an amalgam of animism, Hindu-Buddhist, and Islamic — especially Sufi — beliefs. The beliefs is rooted in Javanese history and spiritualism with the tendency to syncretize aspects of different religions in search of the common ground. This loosely organized current of thought and practice was legitimized in the 1945 constitution and, in 1973, when it was recognized as Kepercayaan kepada Tuhan Yang Maha Esa (Indonesian: Believer of One Supreme God) that somewhat gain the status as one of the agama, President Suharto counted himself as one of its adherents. The Kebatinan or Kepercayaan have no certain prophet, sacred book, nor distinct religious festivals and rituals; it has more to do with each adherents internalized transcendental vision and beliefs in their relations with others and with the supreme being. As the result there is an inclusiveness that the kebatinan believer could identify themselves with one of six officially recognized religions, at least in their identity card, while still subscribe to their kebatinan belief and way of life.
Kebatinan is generally characterized as mystical, and some varieties were concerned with spiritual self-control. Although there were many varieties circulating in 1992, kebatinan often implies pantheistic worship because it encourages sacrifices and devotions to local and ancestral spirits. These spirits are believed to inhabit natural objects, human beings, artifacts, and grave sites of important wali (Muslim saints). Illness and other misfortunes are traced to such spirits, and if sacrifices or pilgrimages fail to placate angry deities, the advice of a dukun or healer is sought. Kebatinan, while it connotes a turning away from the militant universalism of orthodox Islam, moves toward a more internalized universalism. In this way, kebatinan moves toward eliminating the distinction between the universal and the local, the communal and the individual.
Subud is an international spiritual movement that began in Indonesia in the 1920s as a movement founded by Muhammad Subuh Sumohadiwidjojo. (The name Subud was first used in the late 1940s when Subud was legally registered in Indonesia.) The basis of Subud is a spiritual exercise commonly referred to as the latihan kejiwaan, which was said by Muhammad Subuh to be guidance from "the Power of God" or "the Great Life Force".
Muhammad Subuh saw the present age as one that demands personal evidence and proof of religious or spiritual realities, as people no longer just believe in words. He claimed that Subud is not a new teaching or religion but only that the latihan kejiwaan itself is the kind of proof that humanity is looking for. There are now Subud groups in about 83 countries, with a worldwide membership of about 10,000.
Animism has existed since Indonesia's earliest history, around the first century, just before Hindu culture arrived in Indonesia. Furthermore, two thousand years later, with the existence of Islam, Christianity, Hinduism, Buddhism, Confucianism and other religion, Animism still exists in some parts of Indonesia. However, this belief is not accepted as Indonesia's official religion as the Pancasila states the belief in the supreme deity, or monotheism. Animism, on the other hand, does not believe in a particular god. The government of Indonesia often views indigenous beliefs as adat (custom) rather that agama (religion) or as a variant of a recognized religion. Because the government do not recognize animism indigenous tribal belief systems as official religion, as a result followers of various native animistic religions such as Dayak Kaharingan have identified themselves as Hindu in order to avoid pressure to convert to Islam or Christianity. Several native tribal beliefs such as Sundanese Sunda Wiwitan, Torajan Aluk To Dolo, and Batak Malim — although different from Indian influenced Balinese Hinduism — might seek affiliation with Hinduism in order to survive, while at the same time also preserving their distinction from mainstream Indonesian Hinduism dominated by Balinese. In many cases, some of the followers of these native beliefs might convert to Christianity or Islam, at least registered as such on their KTP (identity card), but still uphold and perform their native beliefs.
There are an estimated several hundred Jews in Indonesia, mainly expatriates in the Jakarta area who conduct religious services at home. Some tiny local Jewish community exist in Indonesia, mostly those whom rediscovered their ancestral roots and convert back to Judaism. There are small unrecognized Jewish communities in Jakarta and Surabaya. Like many Jews in the then Netherlands East Indies, some of whose forebears had moved there as early as the 17th century, they suppressed their faith. An early Jewish settlement in the archipelago was through the Dutch Jews who came along for the spice trade. In the 1850s, about 20 Jewish families of Dutch and German origins lived in Jakarta (then Batavia). Some lived in Semarang and Surabaya. Several Baghdadi Jews also settled in the island. Prior to 1945, there were about 2,000 Dutch Jews in Indonesia. Some Jews even converted to Christianity or Islam during the Japanese Occupation, when Jews were sent to internment camps, and the War of Independence, when Eurasians were targeted. In 1957, it was reported around 450 Jews remained, mainly Ashkenazim in Jakarta and Sephardim in Surabaya. The community decreased to 50 in 1963. In 1997, there were only 20 Jews, some of them in Jakarta and a few Baghdadi families in Surabaya.
Jews in Surabaya maintained a synagogue for many years, with sporadic support from relatives and co-religionists residing in Singapore. Beth Shalom closed in 2009 after radical groups protested against Israel's assault on the Gaza Strip. Soon afterward, it was designated a heritage site by the Surabaya government, but it was demolished in May 2013 without warning, as part of a mysterious real estate deal. 
Since 2003, Shaar Hashamayim synagogue has been serving the local Jewish community of some 20 people in Tondano city, Minahasa Regency, North Sulawesi. Currently it is the only synagogue in Indonesia that provides services.
Many believe that atheism is illegal in Indonesia even though there is no specific law that bans atheism. In 2012, atheist civil servant Alexander Aan was sentenced to thirty months in prison for sharing explicit material about the Prophet Mohammed online, sparking nationwide debate. Alexander's lawyers speculated that there were only 2,000 or so atheists in Indonesia, but stated that it was difficult to estimate due to the threat of imprisonment for open atheism.
Although the Indonesian government recognizes a number of different religions, inter-religious conflicts have occurred. In the New Order era, former president Suharto proposed the Anti-Chinese law which prohibits anything related to Chinese culture, including names and religions. Nevertheless, positive form of relations have also appeared in the society, such as the effort from six different religious organisations to help the 2004 Tsunami victims. Subud is a religion founded in Indonesia.
Between 1966 and 1998, Suharto made an effort to "de-Islamicise" the government, by maintaining a large proportion of Christians in his cabinet. However, in the early 1990s, the issue of Islamisation appeared, and the military split into two groups, the Nationalist and Islamic camps. The Islamic camp, led by General Prabowo, was in favour of Islamisation, while General Wiranto was in the Nationalist group, in favour of a secular state.
During the Suharto era, the Indonesian transmigration program continued, after it was initiated by the Dutch East Indies government in the early nineteenth century. The intention of the program was to move millions of Indonesians from over-crowded populated Java, Bali and Madura to other less populated regions, such as Ambon, Lesser Sunda Islands and Papua. It has received much criticism, being described as a type of colonisation by the Javanese and Madurese, who also brought Islam to non-Muslim areas. Citizens in western Indonesia are mostly Muslims with Christians a small minority, while in eastern regions the Christian populations are similar in size or larger than Muslim populations. This more even population distribution has led to more religious conflicts in the eastern regions, including Poso and Maluku communal violence since the resignation of President Suharto.
The government has made an effort to reduce the tension by proposing the inter-religion co-operation plan. The Foreign Ministry, along with the biggest Islamic organization in Indonesia, Nahdatul Ulama, held the International Conference of Islamic Scholars, to promote Islamic moderation, which is believed to reduce the tension in the country. On December 6, 2004, the "Dialogue On Interfaith Cooperation: Community Building and Harmony" conference was opened. The conference, attended by ASEAN countries, Australia, East Timor, New Zealand and Papua New Guinea was intended to discuss possible co-operation between different religious groups to minimise inter-religious conflict in Indonesia. The Australian government, represented by the Foreign Minister Alexander Downer, supported the dialogue by co-hosting it.
On the issue of Ahmadiyyah Muslim community, Indonesia has failed to act and uphold their human rights. Several Ahmadi mosques were burnt in 2008. 126 Ahmadis have become refugees within their own country in the past 4 years.
There is however, indications that religious conflicts regarding erection of place of worships have more to do with business interest than in religious issues. For example dispute over a Bethel Injil Sepenuh Church (GBIS) in Jakarta was due to land dispute dating back to 1957, while the Indonesian Christian Church (GKI) Taman Yasmin dispute in Bogor was due to municipal government plan to turn the church's area into business district. The Taman Yasmin Church in Bogor has been upheld and protected by Supreme Court of Indonesia, but the mayor of Bogor refused to comply the court ruling.
Religion was a census variable in the 1961, 1971, 1980, 1990, 2000 and 2010 Indonesian census and in various intercensal surveys. Due to deemed divisiveness, 1961 census data regarding religion was not published. In 1971, three groups of Christians were recorded: Catholic, Protestant and other. The U.N. Demographic Yearbook 1979 only lists data collectively for all Christians. In 2000 census, only Catholics and Protestants were available as categories.
Note: the drop in the Catholic population between 1990 and 2000 was due to the secession of East Timor in 1999.