Instead, Indonesia is a secular democratic country, but with very strong Islamic influences. Since the early political debates on the topic of the ideological foundations of the Indonesian nation, certain stricter Islamic groups (including some political parties) have spoken out for favoring the establishment of a Muslim country. However, as Indonesia also contains dozens of millions of non-Muslims, while the majority of Indonesian Muslims are nominal Muslims who support the pluralist philosophy of Indonesia's founding fathers, the establishment of an Islamic country (together with implementation of shariah law) has always been regarded as being a trigger for disunity and calls for separatism.

In fact, political parties favoring the establishment of an Islamic country have never been able to gain the majority of the popular vote throughout the political history of Indonesia. Based on the elections results in the country's recent political history (after the end of Suharto's authoritarian New Order), the stricter Islamic parties are actually losing ground to the secular parties, and therefore it seems very unlikely that Indonesia will become a Muslim state in the (foreseeable) future. However, it is true that conservative Islamic streams in Indonesian society seem to have increased their influence on regional and national politics since 2017 (more about this topic below).

The process of Islamization in Indonesia (or more precise, in the region we now know as Indonesia) has been underway for many centuries and is still continuing today. Islam became an influential force through a series of waves (these waves consisted of international trade, the establishment of various influential Muslim Sultanates, and social movements) that are described in more detail below.

However, present-day Indonesian Islam is also characterized by variety as each region experienced its own unique history, tainted by unique and separate influences. From the later 19th century onward, Indonesia - as a whole - experienced a more general shared history because colonizers (and continued by the Indonesian nationalists) put a national framework on top of the regions. This process of unification has also had its impact on Indonesian Islam which - in a slow pace - is losing its variety. But this should be regarded as a logical development within the process of Islamization in the country.

In recent years, media - both national and international - have often reported on attacks on minority religions in Indonesia (such as the Ahmadiyya and Christians). Some radical Muslim groups such as the Front Pembela Islam (Islamic Defenders Front) use violence (or the threat of violence) to achieve their ideals; also against the Muslim community itself, for example by attacking Muslims that sell food at daytime during the holy fasting month Ramadan. It is worrying that the Indonesian government and the Indonesian judiciary do not stand firm against such radical groups, indicating that the government has a weak monopoly on violence. But it should also be stressed, however, that - by far - the majority of the Indonesian Muslim community is highly supportive of a religious pluralist and harmonious society.

Indonesian islands with a Muslim majority population:

1. Sumatra
2. Java
3. Kalimantan (coastal areas)
4. Sulawesi
5. Lombok
6. Sumbawa
7. North Moluccas

Islam in Indonesia, Islands with Muslim majority Population Indonesia Investments

The populous western part of Indonesia contains a relatively much larger Muslim community than the eastern part. As trade played a significant role in the process of Islamization in Indonesia, islands closer to the main trade routes encountered much more Islamic influences. Western Indonesia, part of a global trade network from the dawn of human history, was much more exposed to such trade-related Islamic influences, hence experiencing the rise and fall of Islamic Sultanates from the 13th century. In particular the Strait of Malacca (between present- day Malaysia and Indonesia) was - and still is - one of the busiest sea-lanes for trade.

Meanwhile, if we jump to recent history, Indonesia has been experiencing robust macroeconomic growth, hence the country's middle class is expanding rapidly supported by steadily rising per capita gross domestic product and purchasing power (meaning people can consume more products and services). Moreover, Indonesia's society - just like the trend around the world - is becoming increasingly urbanized (a process that is closely linked to modernization and industrialization).

Given that almost 90 percent of Indonesia's total population is Muslim, this community is highly affected by both developments (namely rising consumption and urbanization). In the country's bigger cities (in particular on Java, Indonesia's most populous island) the Muslim community is showing increasingly consumptive lifestyles. This especially applies to the large moderate Muslim component within this community. They are increasingly living a modern urban lifestyle, equipped with the latest electronic devices and fashion. And while Islamic fashion is on the rise in Indonesia, there remains relatively low demand for Islamic banking and Islamic tourism (in fact, Islamic tourism is mainly a strategy to attract foreign Muslims to spend a holiday in Indonesia).

Arrival of Islam to Indonesia

Although it is difficult to reconstruct the exact development of early Islamization in the archipelago (due to a lack of sources), it seems certain that international trade played a crucial factor. There probably were foreign Muslim traders in maritime Southeast Asia from early on in the Islamic era. The first sources that inform us about indigenous people adhering to Islam originate from the early 13th century.

Meanwhile, gravestones indicate the existence of a Muslim kingdom in North Sumatra around 1211. Perhaps indigenous kingdoms adopted the new faith because it entailed certain advantages in trade as the majority of traders were Muslim. It remains unclear, however, why indigenous conversion to Islam seems to have taken place centuries after the region became acquainted with this religion. Only from the 15th century onward, Islamic kingdoms and sultanates became dominant political powers in the Archipelago, although these powers were to be undermined by European newcomers (the Portuguese and Dutch) starting from the 16th and 17th century.

Varieties of Indonesian Islam

The arrival of Islam to the Archipelago had different impacts on local communities depending on the historical and social context of the area where it arrived. In some parts of the archipelago towns emerged as a result of foreign Muslim traders settling there. In other parts Islam never became the majority-religion, probably due to the distance from the important trade routes (for example eastern Indonesia which is located far away from the big trade routes and therefore is located in a sort of economic vacuum). Meanwhile, in parts where there existed a strong presence of animism or Hindu-Buddhist culture, Islam met profound cultural barriers (such as on the island of Bali which is still dominated by Hindu culture today), or, Islam became blended with the pre-existing (animist) belief-systems (examples of which can still be found in Central Java).

Since the publication of Clifford Geertz's authoritative book 'The Religion of Java' (published in 1960) scholars tend to divide Indonesia's Javanese Muslim community (the largest Muslim community of Indonesia) in two groups:

Abangan; these are traditional Muslims in the sense that they still apply traditional Javanese dogmatic; blending Islam with Hinduism, Buddhism and animist traditions. Members of this group generally have rural backgrounds.

Santri; these can be labeled as orthodox Muslims. They are mainly from urban backgrounds and are more oriented towards the mosque and the Quran.

Geertz actually also recognized a third class, the priyayi (the traditional bureaucracy), but as it constitutes a social class rather than a religious one, it is not included above.

The spread of Islam in Indonesia should not be seen as a quick process stemming from one origin or source but rather as multiple waves of Islamization in coherence with international developments in the Islamic world, a process that is still continuing until today. As described above, Muslim traders coming to the archipelago in the first centuries of the Islamic era can be regarded as the first wave. The second wave we also briefly described above, namely the establishment of indigenous Islamic kingdoms (after a indigenous ruler converted to Islam, his subjects would follow suit). This topic is discussed in much more detail in our precolonial history of Indonesia section.

Two important reform waves aiming for the return to the pure Islam - as it was during the days of prophet Mohammed - were the Wahhabist and the Salafi movements. Wahhabism originates from Arabia and arrived in the archipelago early in the 19th century. The Salafi movement came from Egypt at the end of the 19th century. Both these waves had a big impact on the spread of orthodox Islam in the archipelago.

Another important development for Islamization in Indonesia was the opening of the Suez-Canal in 1869 because it - as it made traveling to Mecca easier - implied a larger amount of pilgrims between Indonesia and Mecca. This consequently intensified Indonesia's contact with the religious centers in the Middle East.

However, these waves of Islamization have also been the cause of tensions and disunity within the Indonesian Islamic community as not everyone agreed with the arrival of an orthodox stream of Islam. For instance, the distinction between modernist (santri) and traditional (abangan) communities on Java are actually the result of the traditionalists' reaction against the reform movement in the 19th century. This division is still visible in the two most influential Islamic organizations in the country today. The Muhammadiyah, a social organization founded in 1912 on Java, represents the modernist Muslim stream that disapproves of the mystical (traditional) Javanese Islam. Currently this organization has around 50 million members. As reaction to the establishment of the Muhammadiyah, traditional Javanese leaders founded the Nahdlatul Ulama (NU) in 1926. Members of the NU are influenced by mystical streams or pre-Islamic elements. Its leadership is also characterized by being more tolerant towards other religions. It has around 90 million members.

Rising Influence of Conservative Islam on Indonesian Politics?

There is some concern about the rising influence of hardline Islamic groups on local and national politics in Indonesia. The concern is that this development is not good for Indonesia's religious pluralism and for the country's minority groups, such as the LGBT community.

In 2014 ethnic Chinese Christian Basuki Tjahaja Purnama (Ahok) succeeded Joko Widodo as Governor of Jakarta. Ahok was the Deputy Governor (2012-2014) but, by law, replaced Widodo when the latter became the seventh President of Indonesia in 2014 (and therefore had to resign as Jakarta Governor). While hardliners did not agree seeing a non-Muslim leading a Muslim majority city, there were no significant troubles up to late-2016.

In late-2016, in the context of Jakarta's 2017 gubernatorial election, Ahok made a blasphemous slip-off-the-tongue when he said some citizens would not vote for him because they are "threatened and deceived" by those using the verse Al-Ma'ida 51 of the Qur'an (which allegedly forbids a Muslim population being led by a non-Muslim leader). After a manipulated video of Ahok's statements went viral on (social) media, fierce criticism emerged, particularly from hardline Muslim groups.

A series of huge demonstrations, organized by hardline groups, took place in Jakarta and put severe pressure on Indonesian society. Religious tensions made many Muslims decide to strengthen their Muslim identity (out of fear of being labeled an infidel). For example, women who previously never wore the Islamic headscarf now started wearing one, while men who rarely used Arab phrases on social media suddenly started using these, or, set a new profile picture on social media depicting them in Muslim clothes. Hence, these religious tensions in fact caused the next wave of Islamization in Indonesia.

Ahok was later trialed for blasphemy, resulting in a very controversial two-year prison sentence for him (possibly even the judges were intimidated by the religious tensions). Meanwhile, Ahok also lost his bid for re-election (being defeated by Anies Baswedan). This was a big victory for the hardliners. Perhaps for the first time these hardliners felt they had influence on Indonesian politics.

The chaos and religious tensions related to Jakarta's 2017 gubernatorial election were likely to extend into Indonesia's 2019 presidential and legislative elections. After all, incumbent President Widodo was seen as an ally of Ahok. Hence, hardliners were also after Widodo. Moreover, controversial presidential candidate Prabowo Subianto reached out to the hardliners as this would boost his chances in the presidential race. Widodo, however, managed to fend off 'attacks' from the hardline groups by selecting renowned conservative Muslim cleric Ma'ruf Amin as his vice-presidential candidate in the 2019 presidential election.

Amin, who is also highly respected among the hardline groups, had in fact testified against Ahok in the blasphemy case, and is also behind the fatwas (a nonbinding legal opinion on a point of Islamic law, sharia, given by a qualified jurist) issued by Indonesia’s Ulama Council (Majelis Ulama Indonesia, or MUI) against the rights of religious minorities, including the country’s Ahmadiyah and Shia communities, as well LGBT people. While these fatwas are not legally binding, they have been used to legitimize increasingly hateful rhetoric by Indonesian government officials against the country's LGBT people and in some cases even fueled fatal violence by Islamists against some religious minorities.

Although religious tensions in Indonesia rapidly vanished after Amin sat next to Widodo (and they also managed to win the 2019 presidential election), the election can also be regarded a victory for conservative Islam as there is now a conservative Muslim cleric on a high political position (with certain political powers). This might set a precedent for future elections. And, interestingly enough, this would not have happened if Ahok's term as Governor of Jakarta had not ended so badly. Thus, while initially - in 2014 - many people (including human rights advocates) applauded the fact that a Christian could become the governor of Jakarta, in the end it would trigger a new wave of Islamization across Indonesia, while strengthening the influence of hardline Muslim groups on Indonesian politics.

Radical Islam in Indonesia

Since the 1990s, Islam has become more visible on the streets in Indonesia and has begun to play a more important role in the daily lives of the Muslims. For example, the number of Indonesian women who wear the headscarf (jilbab or kerudung) has increased significantly, and it has become more common to visit the mosque.

However, it is important to underline that this development of Islamization should not be mistaken for Islamic radicalism (or Islamism). By far most Indonesian Muslims are tolerant towards other religions or other streams within the Islam. Only a small fraction of Indonesian society can be labeled 'radical' or 'hard-line'. And a very small percentage of Indonesian Muslims participate in - or agree with - terrorist activities (although there is concern that this group is growing).

Although Muslim radicalism in Indonesia has been given much attention since the 9/11 attacks in New York (particularly after the Bali and Jakarta bombings in the 2000s), it is not a new phenomenon to the country. Incidences which involved Islamic radicalism have been witnessed before, such as the Darul Islam rebellions in the 1950s, regional rebellions in the late 1950s, the massacres of communists in 1965-1966, an airplane hijacking in 1981, multiple attacks on Christian churches and Buddhist monuments, as well as multiple actions against brothels, bars and casino's in recent decades.

For more detailed information regarding this topic please visit our Radical Islam page.