yes they will

Posted by dan_the_man on Wednesday, 5. March 2008 at 17:20 Bali Time:

In Reply to: Do Next G Mobiles work posted by shubbaz on Saturday, 1. March 2008 at 13:14 Bali Time:

You can call telstra on 125 109 to get international roaming on your account.

or you can buy an indo prepaid sim when you get there.