How much is a traveler affected by Ramadan in Indonesia?

Question

I'm planning to go to Indonesia this summer. However, Ramadan, where Muslims have to fast during the daytime, is going to be from June 18th to July 16th this year (2015).

I'm planning to go to Bali, Java, Sumatra and Sulawesi. Except for Bali, all of those regions are predominantly islamic. I have heard that during the last week of Ramadan and the following week, most Muslims in Indonesia are on holiday and are visiting their home towns and families and that thus public transport is very overcrowded during this time.

How much is a traveler/backpacker affected by Ramadan?

Answer 1

The situation in Indonesia is very similar to Malaysia, and I'll quote my own answer to another question, with minor tweaks when applicable:

While you certainly can get drinks and food, most places that stay open do so a little discreetly, with curtains on the windows etc, and you'll want to show respect to people who are fasting by not eating, drinking or smoking in public. The flip side of the coin is that once the time for buka puasa (breaking the fast) rolls around at sunset, many restaurants will be packed with Muslims, so you may actually want to beat the rush and grab your dinner before 6! Out in the nearly 100% Muslim countryside, though, virtually everything will shut down during the day.

The other travel glitch to beware of is that the end of Ramadan (Eid ul-Fitr, Idulfitri, or Lebaran in Indonesian) is the local equivalent of Christmas, when everybody takes time off and goes back to their families (mudik). This means most transportation is fully booked for several days and even the traffic jams are legendary. Plan ahead so you can avoid travel at this time.

Note that there's significant regional variation though. As in Malaysia, the Chinese community does not observe Ramadan, so any local Chinatown is a good place to be based. In addition to mainly Hindu Bali, which you already noted, northern Sulawesi around Manado is largely Christian and so are the Batak areas of northern Sumatra. I'd aim to be in one of these areas for the Lebaran rush and the following week; ideally Bali, since it's also got the most to see and do. If you're in a backpacker enclave like the Gili Islands, Ramadan will be more or less invisible.

Answer 2

Following my recent experience in Java.

I only stayed a couple of days in Java during the Ramadan, but I think it gave me a good introduction to this special time of the year for the Muslims of Indonesia.

Basically, it was much more easy going than I thought, we did not feel a huge difference before and after the start of the Ramadan. It might have been a little quieter, in the streets but also in monuments. We were able to travel as usual without noticeable changes in the train and buses frequencies. Hotels were still open at usual times. Some shops closed a little more often but still, Indonesian people still worked long hours, even if less than the rest of the year. People were very nice and explained me many things, they're usually happy to answer questions about it, about Islam, and they'll probably ask back a few question about your own country.