Last time I was there, there were a few ATMs inside the international baggage claim area, however none of them was working. Anyway, when you exit customs you will be in the arrivals hall where you'll find transport counters and a couple of currency exchange offices and banks. If you exit that area toward the left side (facing the street) and look left once outside, there will be another ATM there, this one was not working either. I ended up changing money with one of the banks inside. Note....this was in the arrivals section, I don't know about ATM locations in the departures area nor in the domestic terminal. Also, this was a few years ago (about a couple months prior to the Bali bombing), so I'm not sure if the layout is still the same.