In reply to an earlier post,prepaid optus phones can be used anywhere optus has a partner,they automatically have roaming attached,and yes I'm aware Bali is part of Indonesia,but the optus zoo page is contradictory in its statements about availability in Indonesia.In one section it gives rates,another section says no coverage.I have since rung them after all the different answers I recieved,and optus does not have a partner in Indonesia,but were only too happy to unlock my phone.Thank you to all those who responded to my question.