Telstra will manage this with your existing carrier so you can retain your existing number.
Can I switch to Telstra if I'm on a contract with another provider? Yes, you can. But you may have to pay an early termination charge to your existing mobile service provider. It’s a good idea to check with your existing provider before you switch to Telstra.
Can I keep my mobile number when I switch? Yes, you can. Whether you want to go pre-paid or post-paid, Telstra will ‘port’ your number across – it’s a free service. How long does it take? In most cases, it takes just a few minutes. You’ll need to give us some information to aid the switching process. In particular, if your old service was a post-paid plan, you’ll have to provide the account number with your previous provider.
Do I replace my SIM card when I switch? Yes, you will need a new SIM card. Telstra will provide this as part of the activation of your service.
What happens to my calls? You may experience a brief period (lasting a few minutes) where some calls to your mobile may not get through. However, you will still be able to make calls during this time.