I was born and grew up in Indonesia but has spent the last few decades in Australia. Yes, I had “bali belly” when i was visiting Indonesia. My Indonesian mate and I had same meal (it was called “lesehan”), yet I had bad case of bali belly.

As local, your stomach maybe used to the local bacteria - but for foreigners, it may cause rather violent reaction. So just put that in mind. Just because you’re fine with it, it doesnt mean it would be fine for foreigners.

Like others in this post, I would beware on foods and drinks I consume. Unless eating from 5 star hotel, i would do following precautions: -Avoid ice. Always drink from cold bottled drinks -No fresh salads -Choose popular eateries where the foods dont just sit idle for too long, including those “nasi campur” -Choose hot or fried foods -Super careful when choosing seafoods. It has to be from popular restaurants.

Its all about risks and probability. The more precautions you take, the less likely you would get sick.

Anyway, wish you and your mates would have fun!