Can I keep my mobile number when I switch networks?

When you take out a brand new mobile deal from a different network, your SIM will come with a new phone number. Changing numbers can be such a hassle though - why not just keep your old one instead?

The good news is that if you're switching from one UK network to another UK network, you can absolutely keep your old mobile number. It's just a case of getting it transferred over to your new SIM card.

Here's how it's done, along with answers to a few questions you might have about number porting.

How to keep your number

To keep your old mobile number on a new network, follow the steps below. This applies whether you're switching to a mobile phone contract, a SIM-only deal, or pay-as-you-go plan.

1. Get ready to switch

First, make sure you're out of contract on your old plan - otherwise you may face penalty fees. If all is well, you're free to switch to a new deal.

If you have any of your contacts' info stored on your SIM card, you may also want to transfer that to your new phone (if you already have one), your Google account, Apple ID, or another cloud service.

2. Pick a new deal

Find a brand new mobile deal that you want to switch to. Take a look at all the mobile contracts or SIM deals we have here on CompareMyMobile, choose one you like the look of, and click through to order it from the provider's website.

When the SIM card from your new plan arrives, it will have a temporary phone number. But not for long…

3. Get your PAC

Contact your old network and ask for a PAC - a porting authorisation code. It should consist of three letters and six numbers, like ABC123456.

To get one, you can call the network's customer service - or there may be an online form you can fill out.

4. Give it to your new network

Next, contact your new network, and tell them your PAC. You can do this by phone, or again some networks also have an online form to use if you prefer.

You'll need to do this within 30 days of getting the PAC, or it'll expire.

5. You're done!

That's it - your old number is ready to port over to your new SIM. This can be done as soon as the next day, though it may take longer.

Your network will give you some specific instructions to follow on the day of the transfer, which should be fairly straightforward. You'll need to make sure your new SIM is in your phone and switched on, for instance.


How long does it take to switch my number across?

It depends on which networks you're switching between and when you request the port, but it's almost always done within a few days. Sometimes a number port can happen the very next day after you request it.

Will I lose service?

Yes, you'll probably lose service on your new SIM on the day of the transfer, at least for a little while. It could be for as little as a few minutes, though in some cases it'll take a few hours.

If you lose service for an excessively long time, try switching your phone off and on again - this can kick-start the SIM's connection. And if it hasn't finished porting by the end of the day and you still don't have service, contact your network.

It's a good idea to prep for transfer day and be ready for the brief loss in service. Get connected to Wi-Fi in the meantime - that'll still work fine - and let your contacts know that your number won't work for a bit.

Most networks will drop you a text when the port is about to start, or at least let you know what day it'll happen on.

What do I do if my PAC expires?

Not a problem. Just call your old network again and ask for a new one, and pass that on instead.

When should I cancel my plan with my old network?

As long as you're out of the minimum contract terms, you can cancel your old plan as soon as you've signed up to a new deal and got your PAC.