Porting a number in Australia: how it works and how it's abused
Who Called Australia editorial team · Updated: 31/08/2026
Since mobile number portability arrived in Australia in 2001, your number has belonged to you, not your provider: switch networks and take it along. That single design decision shapes what any number lookup can honestly claim — and it created a fraud pattern worth knowing about.
How a port works
You sign up with a new provider and give them the number; the gainingprovider drives the process, confirms your identity, and the number cuts over — often within the hour for mobiles. There's no need to call your old provider first (they'll try to win you back; that's your call). Behind the scenes, carriers maintain shared routing data so calls to your number find its current network, whichever range it originally came from.
What porting does to register data
The ACMA numbering register — the data behind this site — records range allocations: Telstra holds 0412, Optus holds 0411's neighbouring ranges, and so on (the full prefix history). Ports happen underneaththat layer and aren't published. Two consequences for reading our pages:
- A number's page names the holder of its range — solid, official data about the numbering space, and a good prior for older numbers, but not proof of the current network of one specific service.
- Statistically, most numbers still ride their original network, so range data remains genuinely informative — it just can't be treated as a per-number guarantee. We phrase it accordingly everywhere.
The abuse: unauthorised porting and SIM swaps
Your mobile number is a de-facto security key: banks, email and myGov all send codes to it. In a SIM-swap, a criminal armed with your leaked personal details ports your number away, and every SMS code follows. The 2020 identity-verification rules made Australian ports significantly harder to hijack — providers must confirm identity strongly before moving a number — but the defence checklist is still worth doing:
- Ask your provider about a porting PIN / port block on your account.
- Prefer app-based or hardware second factors over SMS where services allow it.
- Sudden "SOS only" on your phone plus password-reset emails = act now: call your provider from another phone and your bank right after.
- Report identity theft at ReportCyber and get recovery help from IDCARE (1800 595 160).
Related: which carrier owns which mobile prefix · the 60-second scam check.
Frequently asked questions
Does porting my number cost anything?
The gaining provider handles the port and rarely charges for it — they want your business. Mobile ports often complete within minutes to hours on a working day; landline and complex ports can take days. Your old contract's exit terms are a separate matter from the port itself.
Why does this site name a different carrier than the one my friend actually uses?
The ACMA register records who holds the number range, which reflects the original allocation — not individual ports. Once a number is ported, the register keeps naming the range holder while the service lives on another network. That's why we always say 'range allocated to X', never 'this number is on X'.
What is SIM-swap fraud, and what does porting have to do with it?
A criminal who has gathered your personal details asks a provider to port your number to their SIM. Once your number is theirs, SMS security codes for your bank and email flow to them. Since 2020, providers must verify identity more strongly before porting — but treating your number as a security credential and adding a porting PIN with your provider remains smart.
Can I check whether a number has been ported?
There's no public per-number porting register. Carriers resolve routing between themselves in real time. Practically: treat any carrier attribution — including ours — as 'holder of the range' rather than the current network of an individual service.