PAC Code: How to Keep Your Mobile Number When Switching (2026)

Switching mobile networks used to mean either losing a number you had used for years or spending an afternoon on hold. Since 1 July 2019, Ofcom's "text-to-switch" rules made it almost effortless: one free text gets you a PAC code, and your number moves to the new network by the next working day. This guide explains exactly what a PAC is, how to get one, what it costs (nothing), and how it differs from a STAC — plus the one important exception for landline and VoIP numbers.

What is a PAC code?

PAC stands for Porting Authorisation Code. It is a short code your current mobile network issues that lets you keep your existing mobile number when you move to a different network.

"Porting" is the industry term for transferring a phone number from one provider to another. The PAC is the authorisation that says: yes, this person owns this number, and they want to take it with them. Without it, switching networks would mean accepting a brand-new number — and reprinting every business card, van decal and website listing you own.

A PAC is valid for 30 days from the moment it is issued. If you do not use it within that window, it simply expires and you can request a fresh one.

How to get a PAC code (and the other switching texts)

You do not need to call anyone, log into an account, or explain why you are leaving. Everything is done by free text message. Ofcom requires every UK mobile provider to support these three shortcodes:

Send the relevant word to the relevant number from the phone you want to switch. Your provider replies — usually within a minute — with the code and a summary of anything you still owe.

If you are unsure whether you are still in contract, send INFO to 85075 first. It tells you your end date and any early-termination or handset balance before you commit to anything.

How to switch while keeping your number

The whole process is genuinely four steps:

1. Text PAC to 65075 from the mobile you want to keep. Wait for the reply containing your code.
2. Choose your new network and start the sign-up for the plan you want.
3. Give the new provider your PAC when prompted during sign-up.
4. Wait for the switch to complete — including the move of your number — by the next working day.

That is it. You do not have to ring your old provider to cancel; handing the PAC to the new network triggers the cancellation automatically once the number ports across. You keep using your old SIM until the new one activates, so you are not left without service.

How long does it take?

Once you give your PAC to the new provider, the switch — including moving your number — completes by the next working day. In practice that usually means a short window where the old SIM stops working and the new one takes over. Plan for it the same way you would a small maintenance job: ideally not in the middle of your busiest trading hours.

Does a PAC code cost anything?

Requesting a PAC is free, and switching while keeping your number does not carry a fee of its own.

What you might still owe is anything outstanding on your current agreement — for example, the remaining months on a fixed contract or an unpaid handset instalment plan. That is a separate balance, not a charge for switching. The INFO text to 85075 spells out exactly what (if anything) you owe, so there are no surprises on your final bill.

PAC vs STAC: which do you need?

The two codes do opposite jobs, and the difference matters:

• PAC (text to 65075) — use this when you want to keep your number. Your number ports to the new network.
• STAC (text to 75075) — use this when you are happy to let the number go. STAC stands for Service Termination Authorisation Code; it cancels your service cleanly without porting anything.

For a business, the answer is almost always PAC. Your mobile number is printed on listings, saved in customers' phones and tied to your reputation. Losing it is rarely worth it. Reach for a STAC only when you genuinely want a fresh number and a clean break.

Landlines and VoIP work differently

Here is the exception that trips people up: PAC and STAC codes are for mobile numbers only.

If you want to move a landline or VoIP number — say an 01, 02 or 03 geographic number — you do not request a PAC. Instead, you simply sign up with the new landline or VoIP provider, and they arrange the number transfer with your old provider on your behalf. The mechanism is different, but the outcome is the same: you keep your number.

If you are weighing up a move and want to understand how numbers map to places, our guide to UK area codes breaks down the geographic codes. And if you are rethinking your whole setup, see our roundup of the best small business phone system options.

Keeping your number is only half the job

A number is only worth keeping if the calls to it actually get answered. The most common reason small businesses lose work is not a wrong number on a listing — it is a ringing phone that nobody picks up because everyone is on a job, driving, or already on another call.

This is where an AI virtual receptionist earns its place. Whether you have just ported a long-held mobile number to a cheaper network, or set up a fresh business line, Orval answers every call in your business name, 24/7. It books appointments, captures lead details and passes on the urgent ones — for a fixed price from £19.99/month, with no per-minute fees.

The point is simple: switching networks protects the number your customers already know. Making sure that number is always answered protects the work those customers bring you. If you are comparing providers, our guide to the best virtual receptionist UK services walks through what to look for.

In short

• A PAC (Porting Authorisation Code) lets you keep your mobile number when you switch networks.
• Get one by texting PAC to 65075. It is free and valid for 30 days.
• Give the PAC to your new provider; the switch completes by the next working day.
• Text STAC to 75075 only if you want to leave without keeping your number, and INFO to 85075 to check charges first.
• Landline and VoIP numbers do not use a PAC — the new provider arranges the transfer for you.

Keep the number. Then make sure someone — or something — always answers it.

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Frequently Asked Questions

What does PAC stand for?

PAC stands for Porting Authorisation Code. It is the code your current mobile network gives you so you can keep your number when you move to a new network.

How do I get a PAC code?

Text the word PAC to 65075 for free. Your current provider texts your PAC back, usually within a minute. The code is valid for 30 days.

Does getting a PAC code cost anything?

No. Requesting a PAC and switching while keeping your number is free. You may still owe any outstanding contract or handset balance — text INFO to 85075 to see exactly what you owe before you switch.

What is the difference between a PAC and a STAC?

A PAC lets you switch network and keep your number. A STAC (Service Termination Authorisation Code) cancels your service when you do NOT want to keep your number. Text PAC to 65075 to keep it, or STAC to 75075 to leave it behind.

Do I need a PAC code for a landline or VoIP number?

No. PAC and STAC codes are for mobile numbers only. To move a landline or VoIP number you simply sign up with the new provider and they arrange the transfer with your old one.