PAC code or STAC code: which one do you need?

Key takeaways

• A PAC (Porting Authorisation Code) lets you keep your mobile number when you switch networks. Text PAC to 65075 from the SIM you're leaving, and the code should arrive free of charge within a minute.
• A STAC (Service Termination Authorisation Code) lets you switch and start afresh with a new number. Text STAC to 75075 from the SIM you're leaving.
• PAC and STAC codes work the same way across all UK networks, including EE, O2, Vodafone and Three. Each code is valid for 30 days and is provided to the new provider, which arranges the switch, so you don't need to cancel the old plan first.

 

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You've found a better deal, the new SIM is on its way, and then a form asks for a PAC or STAC code. Cue a small wobble. Which one do you need, and what happens if you pick the wrong one?

The good news is that it's simpler than it sounds, and a text message usually sorts it out. Here's what each code does, how to get one, and how to use it.

What is a PAC code?

PAC stands for Porting Authorisation Code. It lets you transfer your existing mobile number from one provider to another. You may also see it called a PAC number, but it's the same thing.

A PAC is nine characters long: three letters followed by six numbers, such as ABC123456. Give it to your new provider, and they'll arrange the transfer with your old provider, usually by the end of the next working day. A PAC applies to a single number, so if you're moving several lines, you'll need a code for each.

What is a STAC code?

STAC stands for Service Termination Authorisation Code. It's used when you're leaving a network and don't want to take your number with you. Instead of moving your number, a STAC closes it down, and your new provider gives you a fresh one.

A STAC is also nine characters, but the order is reversed: six numbers followed by three letters, such as 123456ABC.

One heads-up. A STAC only works once your new provider has it. Request one and forget about it, and your old plan stays open, so you could keep getting billed. If you're not joining a new provider, ask your old one to cancel the plan directly instead.

PAC or STAC: what’s the difference?

Code	What it does	How to request it	Format	Valid for
PAC	Keeps your number when you switch	Text PAC to 65075	3 letters, then 6 numbers	30 days
STAC	Closes your old number so you can get a new one	Text STAC to 75075	6 numbers, then 3 letters	30 days

A simple rule: if you want the same number, ask for a PAC. If you don't mind a new one, ask for a STAC.

How do I get a PAC or STAC code?

Texting is the fastest way for both codes, and the same two numbers work on every UK network.

How do I get a PAC code?

Text PAC to 65075 from the SIM you're leaving. Your provider should reply within a minute with your PAC and any early termination charges.

• The text is free thanks to Ofcom's text-to-switch service.
• Some networks also ask for your date of birth in ddmmyy format. For a 1 January 1990 birthday, that's PAC010190.
• You can also request a PAC by phone, via your provider's app or online account, or in store.
• If your old SIM is lost or broken, your old provider can issue a PAC another way.

How do I get a STAC code?

Text STAC to 75075 from the SIM you're leaving. Your provider should reply within a minute with your STAC and details of any early termination charges.

• The text is free, and the number is one digit away from the PAC number, so double-check the first digit before sending.
• Some networks also ask for your date of birth in ddmmyy format, such as STAC010190.
• A STAC can also be requested by phone, via your provider's app or online account, or in store.

How do I use a PAC or STAC code?

A PAC or STAC does nothing on its own. It only works once your new provider has received it.

How do I use a PAC code?

Give your PAC and the number you want to keep to your new provider. They’ll arrange the move with your old provider, usually by the end of the next working day.

1. Choose your new plan and sign up.
2. Enter the PAC and the number you want to keep when your new provider asks, usually at sign-up or in their app or online account.
3. Keep your old SIM in your phone. It continues working until the switch completes.
4. When the old SIM loses service, put the new SIM in and restart your phone. Expect a short gap in service on switch day.

How do I use a STAC code?

Give your STAC and the number you want to close to your new provider. That lets your old network end your service, and your new provider issue you a new number.

1. Choose your new plan and sign up.
2. When your new provider asks, enter the STAC and the old number you want to close.
3. Your new provider arranges with your old network to end the old service, usually by the end of the next working day.
4. Check that the old plan has closed.

How long does a PAC code last?

A PAC lasts 30 days from the day you request it. If it expires before your new provider has used it, you'll need to request another from your old provider. It's free to request again. A STAC lasts 30 days too.

Once your new provider has the code, the switch usually completes by the end of the next working day. Ofcom says any loss of service during a switch shouldn't last longer than one working day.

Why isn't my PAC code working?

Most problems are easy to fix, and your number isn't lost. The usual suspects are:

• The code has expired. Request a fresh one.
• The code has a typo. Check every character against the text you were sent.
• The code and number don't match. A PAC only works with the number it was issued for.
• The wrong code has been used. A STAC and a PAC look similar, so check which one the form is asking for.
• The account details don't match. The name and address you give your new provider need to match your old account.
• The old account has a problem. An unpaid balance or a suspended account can hold things up.

If none of those fit, contact your new provider first, as they run the transfer.

Joining SMARTY?

With SMARTY, you can add your PAC or STAC when you set up your account, or later in your account settings online or in the app. Once your SIM is active, your number usually transfers within one working day.

Our help articles on keeping your number and leaving your number behind walk you through each step. And if you're ever leaving SMARTY, the same text to switch numbers works with your SMARTY SIM.

FAQs

1. How long does it take to transfer a mobile number to a new network?

Once a new provider has the PAC, a mobile number usually transfers by the end of the next working day. Requests made late in the day, at weekends or on bank holidays can take an extra day or so. Ofcom says any loss of service during a switch shouldn't last longer than one working day.

2. Can I cancel my old plan before switching and still keep my number?

Usually not. A cancelled number generally can't be transferred, so request a PAC first and give it to the new provider, who then closes the old plan. If a plan has already been cancelled, contact the old provider straight away to ask whether the number can still be transferred.

3. Is it free to get a PAC or STAC code?

Yes. Texting PAC to 65075 or STAC to 75075 is free. The reply may show early termination charges or remaining credit, which are separate from the code itself.