Dear Lifehacker, I'm with Vodafone (heh). So are the rest of my family, and we all have prepaid cheap phones on either flexi-caps or 365-day credit deals (with about $20 stored). We're looking at moving to a different provider (Virgin, perhaps). Can we move networks and keep our phone numbers? We're not interested in moving if we can't keep the number. And how would we go about doing so? Thanks, Prospective Network Migrant
The short answer is: yes, you can. Mobile phone numbers in Australia are entirely "portable": when you change providers, you can take them with you. And since you're not signed to a contract, you've got nothing much to lose in the process, other than the existing credit in those long expiry accounts — anyone moving in that scenario might as well make a few long calls before they switch networks. (If you were on a contract, you could still move your number, but you'd have to pay out the remainder of the contract, which could be expensive.)
The process isn't complicated: simply apply to the new provider you want to use, and explain to them that you want to move your existing number. They'll handle the porting process, and let you know if you need a new SIM card. In general, this process can take place within a couple of hours, but technical delays aren't entirely unknown — don't schedule the switch if you know you'll have an urgent need for your phone that day.
The most common issue you'll face is that your existing mobile phone may be locked to your current provider, meaning that it won't work on any other network. This often happens if you purchase a phone cheaply as part of a prepaid deal.
If that's the case, you'll either have to pay your current provider to unlock the handset, or purchase a new one. Given how cheaply you can purchase a basic handset these days, it likely makes more sense to do that than to have your old one unlocked.
ACMA, which regulates the mobile industry in Australia, has a detailed FAQ covering number portability which highlights other issues to consider. If your entire family is shifting, you might want to take advantage of deals offering free calls on the same network; we recently rounded up the current options for that (in that category, Virgin does indeed have one of the most straightforward offers).