How to Port Your Mobile Number in Australia

The thing people dread most about leaving their telco isn't the paperwork or the new SIM. It's the number. Fifteen years of contacts, your bank, the kids' school, every two-factor code you've ever been sent, all tied to those ten digits. So they stay put on an overpriced plan out of pure fear.

Here's the part that fear skips over: the number is yours to take. Learning how to port your mobile number in Australia takes about five minutes of reading and, in most cases, a couple of hours to actually happen. You keep the number. You just change who bills you for it.

Let me walk you through how it really works, what trips people up, and the single mistake that genuinely can cost you your number.

Your number is yours, the rule most people miss

Number portability isn't a favour your telco grants you. It's the law. Under the rules the ACMA sets out in the Telecommunications Numbering Plan, your provider cannot refuse to release your number when you leave. They might try to talk you out of going. They can't actually stop you.

Think of your mobile number like a rental you're allowed to take with you to the next place. The walls change. The address on your door stays the same. That's portability in one sentence.

One detail surprises almost everyone: you don't contact your old provider to start a port. You sign up with the new one, and they do the work behind the scenes. Your old account closes automatically once the number moves across. Why that order matters, I'll get to in a minute.

What you'll need before you start

Porting goes sideways for one reason more than any other: mismatched details. Your new telco checks what you give them against your old account, and if a digit is off, the whole thing stalls.

Before you begin, have these ready:

• The mobile number you're keeping

• Your account number or service details from your current provider, matching a recent bill (usually less than 90 days old)

• A photo ID such as an Australian driver's licence or passport

• The phone with that SIM in it, switched on and able to receive a text

That last one matters more than it looks. I'll come back to it.

How to port your mobile number in Australia, step by step

The actual process is shorter than the list of things you need for it.

First, choose and sign up with your new provider. Pick the plan, order the SIM or eSIM, and during sign-up you'll see an option worded something like "transfer my existing number" or "bring my number across." Choose that, not "give me a new number." People rush this screen and end up with a brand-new number they then have to undo.

Second, enter your details exactly as your current telco has them. Same name, same number, same account reference. This is the step where tiny errors cause big delays.

Third, pass the identity check. Australia tightened its pre-port verification a few years ago to stop number theft, so your new telco sends a one-time code by SMS to the number you're moving. You get a short window to enter it back, often around 30 minutes, so don't kick off a port right before you walk into a long meeting. If the phone is lost, stolen or broken and can't receive that code, you can verify with ID documents instead.

Fourth, wait. Once you've confirmed the code, the request goes to your old carrier and the number starts moving. You don't need to call anyone or cancel anything.

That's it. Same number. New plan.

How long does porting take?

Faster than most people expect. Industry rules require 90% of mobile ports to finish within three hours, and 99% within two business days. In practice, a straightforward prepaid-to-prepaid move during business hours often lands in well under an hour.

A few things stretch it out: starting late at night, mismatched account details, or porting on a weekend or public holiday. If you're switching specifically so you don't miss an important call, do it on a quiet weekday morning and give yourself a buffer.

During the changeover there's usually a brief window where your old SIM has stopped working and the new one hasn't fully taken over. Calls and texts can drop out for a bit. Plan around it. Don't port the morning your bank is meant to ring about a home loan.

The mistakes that actually cause problems

Most porting horror stories trace back to the same short list of errors.

The big one: don't cancel your old service first. I know it feels like the responsible thing to do. It's the opposite. Starting a port is what closes your old account, so if you cancel ahead of time, the number can drop back into the pool and you may lose it for good. Let the port do the cancelling.

Next, your authorisation has a shelf life. The new telco's request generally needs to be acted on within about 90 days, which is rarely an issue unless you start a port and then wander off for months without finishing it.

Third, and this is the one people forget in the rush toward a cheaper plan: porting your number does not wipe out money you still owe. If you're mid-contract or paying off a handset, that balance follows you. The number moves. The debt doesn't vanish. Check what you owe before you jump, especially if there's a phone on a payment plan.

Honestly, the trickiest cases aren't technical at all. They're business numbers, or numbers registered to a company or a partner, where the person doing the porting isn't the listed account holder. If that's you, sort out who the authorised contact is first, or the identity check will simply block you.

A quick word on porting fraud

The reason that SMS code exists is a grim one, and worth knowing. Criminals used to hijack numbers by porting them onto a SIM they controlled, then intercepting the victim's bank verification codes. The pre-port verification step shut a lot of that down.

What it means for you is simple. If you ever get an unexpected message saying your number is being transferred and you didn't request it, treat it as an emergency. Contact your provider straight away, and report it to police if money is involved. A port you started, you'll be expecting. One you didn't is a flashing red light.

Common questions about porting your number

Will I lose service while my number ports? Briefly, sometimes. There's often a short gap during the switch where neither SIM fully works. It usually clears within the hour.

Do I need to tell my old telco I'm leaving? No. The port itself closes your old account. Calling them first just invites a retention offer.

Can I port a prepaid number? Yes, the same way as postpaid. Any leftover prepaid credit generally stays behind, though, so spend it first.

What if my details don't match? The port stalls until they line up. Pull out a recent bill, copy the account number and name exactly, and try again.

Once your number lands on the new network, there's sometimes one last small job: getting your mobile data and picture messaging working on the new plan. If that's you, our APN settings guides cover it provider by provider. And if you'd rather read the rules from the source, the ACMA's rules for porting a phone number spell out exactly what telcos are and aren't allowed to do.

Pick a calm weekday morning, keep your old bill in front of you, and the whole thing turns out far less dramatic than the fear that kept you on the wrong plan in the first place.