I notice you say you want to be able to put an Australian number on your CV before you fly, which you'll be reachable on after you land.
There is an alternative option, by buying an Australian phone number through a VOIP service which routes calls to that number to an app via the internet.
One such service is Local Phone's Incoming Number service. I've got a thread on Software Recommendations asking if there are any better alternatives.
These services give you a genuine local landline number of your choice. It'll be just like any other Australian number, but when people call it, the call is routed via the internet to an app on your phone on computer, avoiding international charges. Australians can call you on landlines and mobiles just as easily and cheaply as if calling their neighbour, and you can receive the calls anywhere in the world with an internet connection.
Most such services also let you pay to make local calls. For the person you call, it looks just like you called them from this normal Australian landline number, and they can call you back or save the number in contacts just like a normal phone call.
Advantages over importing a SIM:
- You can start making and receiving Australian calls right now, at local rates
- You can keep the same number when you get there - many services will also let you have it routed direct to your new Aus mobile number, so you can receive calls both when online with no phone signal, and with phone signal but offline
- When, in future, you take trips home and swap your Australian SIM for your home (Iranian) SIM, you can still continue to receive calls to your Australian number
Skype used to offer such a service, called "Skype Numbers". However, I wouldn't recommend this right now due to a major bug with Skype that has existed for over a year and makes Skype numbers almost worthless.
There are many long, long, angry threads on Skype's forums about this, but the quick summary is, Skype currently completely ignores incoming calls apart from while, or 5-15 minutes after, your device's screen is switched on with the Skype app open filling the screen. It doesn't even give missed call notifications, even if you're online and Skype thinks it's "active" and running in the background. [UPDATE] In the latest version of Skype the problem is even worse, you can't even check voicemail messages any more.
This makes it completely useless for receiving calls, which is 99% of the point of having one. I've got a question on the Android site looking for workarounds, but haven't found one yet.
I'd only recommend Skype numbers if a) you can predict when you're likely to be called, so you can sit there refreshing the Skype app when they call (even then, it still sometimes fails), or b) if you spend all day, every day sat at a PC or Mac (these seemingly can receive calls), and never leave your desk.