Transfer your mobile number from T-Mobile to O2

Leaving T-Mobile

How to switch from T-Mobile and transfer my number to O2

T-Mobile customer services can be contacted by either dialing 150 from a T-Mobile SIM, or 0207 362 0200 from another phone, to request your "Port Authorisation Code" (PAC) at the same time that you give your notice of leaving TMobile.

If you wish to use the 'text-to-switch' service, simply SMS text PAC to 65075 free from your T-Mobile SIM to request a PAC code by text message and begin the porting process.

  • T-Mobile will provide your Porting Authorisation Code (PAC) either by SMS text message, via email, or over the phone if you contact them.
  • A PAC number is valid for 30 days. If you don't use it within thirty days it will expire and you will need to request a new one.
  • Your T-Mobile online account settings will remain active until your number has been ported over to the new network. After the transfer is complete, your account will be automatically closed.

While you wait for your Port Authorization Code from T-Mobile, get the best O2 offer for you. Many of these exclusive mobile phone deals are only available online, directly from the network providers listed here.

Got your PAC code from T-Mobile?

Provide your PAC code from T-Mobile to O2 online who will then be able to port your existing phone number from T-Mobile. They will tell you what day the transfer is due to take place (usually within 48 hours).

Important: Do NOT cancel your SIM only or mobile contract before switching, otherwise you may lose your existing phone number and be unable to port it over. Once you give your new network provider your PAC code, your old billing account will be closed automatically when your number is successfully ported over.

Note: Credit on Pre-Pay / PAYG (Pay-As-You-Go) accounts cannot be transferred over and so any remaining credit balance will be lost after the switch is complete. If you have any credit left, one good option is to donate it to a charity by SMS text message before porting your number.

Joining O2

How to switch to O2 and keep my T-Mobile number?

First get your O2 package and activate your new SIM card.

Once you have done that, get the following information ready to follow the step-by-step instructions:

  • Your old T-Mobile mobile phone number you want to keep.
  • The Porting Authorisation Code (PAC) from your previous T-Mobile network.
  • The expiry date of the PAC number (valid for 30 days from the date of issue).
  • The temporary mobile number from your new O2 SIM card activation.
  • You may also need the new O2 SIM card serial number found on the back.

Contact O2 customer services and ask to transfer your old number. You can reach them either from your 02 mobile phone on 4445 for Pay As You Go, or 202 for Pay Monthly contracts. Alternatively from a landline: dial 0344 8090222 for Pay As You Go customer Service or 0344 8090202 for Pay Monthly customer Service.

Alternatively, you can fill in the online O2 form and they will contact you when the transfer is complete.

Note: You may lose network service for a short period on the day of transfer. If this happens, turn your phone off and on occasionally, until you see the O2 signal on your mobile phone screen. This will indicate that the transfer is complete, and you can now use your existing phone number in your new mobile network provider.

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About O2

O2 is a mobile network operator and telecommunications services provider in the United Kingdom, under the company name of Telefonica UK Limited. The company was originally formed in 1985 as Cellnet by the BT Group and was one of the earliest mobile phone networks to launch in the UK, and later rebranded as O2 UK.

02 is one of the largest network operators in the UK and provides 2G, 3G, 4G and 5G services to millions of customers in the United Kingdom, as well as to other mobile virtual network operators (MVNO).

About T-Mobile

T-Mobile UK is a mobile network operator in the United Kingdom, owned by Deutsche Telekom since 1999, and originally launched as One2One.

In 2009, Deutsche Telekom and Orange SA announced that the T-Mobile network was to be merged with Orange UK in a joint venture with EE Limited to form the UK's largest mobile network.