The many religions that you encounter during atrip to Indonesia contribute to enrich the cultural heritage of the archipelago. It is wonderful feeling to be there and experience the peace among all this diversity.
Indonesia is the country with the largest number of Muslims in the world. Nearly 90% of its total population are Muslims. However, even though Islam is the dominant religion of the country, sharia does not apply in Indonesia. A small but interesting detail on the application of religious standards: the Islamic veil is mandatory in religious schools, but is prohibited in state secondary schools!
If you want to visit a mosque during your stay in Indonesia, it is important to dress properly, otherwise you may not be able to enter. You will often find people at the entrance to temples who lend veils to women who don't have one.
The island of Bali is composed entirely of Hindus! It is a striking contrast when you come from Java, for example. Religious practice enters into all the small gestures of everyday life. It is fascinating to observe this fervour and these beliefs during a trip to Bali.
To enter a temple in Bali it is necessary to wear a sarong, a large piece of fabric wrapped around the waist. Not to do so would be considered a great lack of respect towards your host.
The Chinese populations are traditionally Buddhists. Despite the relative peace between the religions, clashes are not unknown. Unfortunately, religion is often used as an excuse against the Chinese elite, which controls a large part of the economy. Thus Buddhist temples are often the target of attacks and arson.
In this regard, the famous site of Borobudur in Java, which is listed as a UNESCO world heritage site, is one of the most important Buddhist monuments in the world.
Finally, during a visit to Indonesia, I suggest that you do not mention that you are a non-believer if that is the case, because this might be poorly accepted by the locals. Interestingly, the latter must obligatorily registertheir religionon their identity papers, choosing among the six officially recognised religions. If they refuse to do so, it is under penalty of being regarded as communists, a very serious crime! All of these religions are practiced in a unique blend of ancestral and present-day beliefs. This religious syncretism explains the uniqueness of ritual practices in the whole of the archipelago.