Get Three PAC code to keep my number & transfer to O2 network

Keep my Three number

How to get a PAC code from Three & transfer my number to O2

Request your Three PAC code by calling Three customer service on 333 from your 3 Mobile handset or by dailling 0333 338 1001 from any other phone or landline, and ask for your 3 PAC code or "Port Authorisation Code".

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

  • Three will provide your PAC code (Porting Authorisation Code) 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 Three account will remain active until your number has been ported over to your new O2 network. After the transfer is complete, your old Three account will be automatically closed.

While you wait to get your Three PAC code, find the best O2 online offer for you. Many of these exclusive mobile phone deals are only available online, directly from the network providers listed here.

Got your Three PAC code?

Provide your PAC code from Three to O2 who will then be able to port your existing Three number. 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 current phone number and be unable to port it over. Once you give O2 your Three PAC code, your old Three billing account will be closed automatically when your mobile phone 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.

Transfer my number to O2

How to switch to O2 and keep my Three 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 Three mobile phone number that you want to keep.
  • The Three PAC code (Porting Authorization Code) from your previous 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 as an additional security check.

Contact O2 customer services with your PAC code and let them know you wish to transfer your old number to O2. You can reach them either from your 02 mobile phone on 4445 for Pay As You Go, or 202 for Pay Monthly contracts.

If you are calling 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 old phone number in your new mobile network provider.

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Compare O2 vs Three

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).

O2 Network Features

2G Network Coverage: Yes

3G Network Coverage: Yes

4G Network Coverage: Yes

5G Network Coverage: Yes

WiFi Calling: Yes

4G Calling (VoLTE): Yes

Data Rollover: No

Tethering Allowed: Yes


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.

Founded in 2002, Three operates 5G, 4G and 3G services within the United Kingdom, and is the only UK network operator not to offer 2G coverage.

Three Network Features

2G Network Coverage: Yes

3G Network Coverage: Yes

4G Network Coverage: Yes

5G Network Coverage: Yes

WiFi Calling: Yes

4G Calling (VoLTE): Yes

Data Rollover: No

Tethering Allowed: Yes