Note, all iPhone 5 models are already unlocked, so you can go ahead and use another sim card in your device without having to do anything else!
For all other iPhones models, see here.
Dial *#06# into your handset and you will see the serial number of your phone (IMEI). Then, call the unlocking centre on 125 8880 and the request will be submitted. After 72 hours, the process will be complete, so simply connect your device to iTunes.
Depending in your specific model, the unlock fee may cost between $50-$150.
Unfortunately, we could not determine the cost for unlocking other devices, or even whether or not they are unlocked to begin with. We suggest you contact customer support directly at 125111.
Post-Paid iPhone customers
Whether or not you’re currently with Telstra, any iPhone purchased from their company can be unlocked by using this online service. After 72 hours, the process will be complete, so simply connect your device to iTunes.