Porting your mobile number from Three to O2

Leaving Three

How to switch from Three & transfer your mobile number to O2

Call Three on 333 from a 3-Mobile handset or 0333 338 1001 from any other phone or landline, and ask for your "Port Authorisation Code" or PAC number.

If you wish to use the 'text-to-switch' service, simply SMS text PAC to 65075 free from your Three SIM to get your PAC code by text and begin the porting process.

  • Three will provide your Porting Authorisation Code (PAC) either over the phone, by SMS text message or via email.
  • A PAC code 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 Three account will remain active until your number has been ported over to the new network. After the transfer is complete, your Three account will be automatically closed.

Many of the top mobile phone deals are available exclusively online, directly from the network providers listed here. So once you have received your Port Authorization Code from Three, get the best O2 offer suited to you.

Finally, provide your PAC code to your new O2 mobile network operator who will then be able to port your existing phone number from Three. They will tell you what day the transfer is due to take place (usually within 48 hours).

Important: Do NOT cancel your contract before switching, otherwise you may lose your existing phone number and be unable to port it over. Once you provide your new network provider with your PAC code, your old account will be clsoed automatically once the 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 before porting your number.

Joining O2

How to switch to O2 & keep your Three mobile number

The first step is to sign up with O2 to get your new SIM card.

Once you have done that, ensure you have the following information ready:

  • Your original mobile phone number you want to keep.
  • The Porting Authorisation Code (PAC) from your previous Three 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.
  • You may also need the new SIM card 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.

Visit O2 online for more information and their latest offers on mobile phone deals.

About O2

O2, the trading name of Telefónica Europe plc is a European broadband and mobile telephony company that originated as a collection of worldwide telecommunications companies, known in the later half of the 1990s as BT Wireless, and a global mobile data business known then as Genie Internet, both subsidiaries of British Telecommunications.

About Three

Three is the brand name of CK Hutchison Holdings under which several UMTS-based mobile phone networks and Broadband Internet Providers are operated in Australia, Austria, Denmark, Hong Kong, Macau, Indonesia, Ireland, Italy, Sweden, and the United Kingdom.

The company was founded in 2002. Three operates 3G and 4G services, and maintains a national roaming agreement with Orange to provide 2G services where 3G is unavailable.