Switch from Three to O2
Keep your phone number when you switch from Three to O2. Here's how in 3 simple steps.
Switching from Three to O2 is a great option for customers who want access to O2's Priority rewards and a reliable alternative network. O2 runs on the Telefonica infrastructure and offers strong coverage across the UK, along with perks like free access to O2 Priority for exclusive deals and event tickets. The switch is quick and your number moves with you.
Important Warning
Do NOT cancel your contract manually. If you cancel before transferring your number, you will lose it permanently. Your old contract will automatically cancel once the transfer completes.
Pre-Switch Checklist
- Back up your data: Contacts, voicemails, and saved messages won't transfer.
- Unlock your phone: Ensure it's not locked to your old network if you plan to keep using it.
- Check Early Termination Fees: Text INFO to 85075 to see if you'll incur charges for leaving early.
How to Switch from Three to O2
Get your PAC code from Three
Text PAC to 65075 from your Three phone to get your PAC code delivered by text within 60 seconds. Alternatively, call Three on 333 from your Three handset or on 0333 338 1001 from another phone to request the code verbally. You can also obtain your PAC through your Three account online at three.co.uk. The PAC code remains valid for 30 days.
Give your PAC to O2
Browse O2's plans at o2.co.uk and select the deal that works for you. When placing your order, choose to keep your existing number and provide the PAC code you received from Three. You can also visit an O2 store or call O2 on 0344 809 0202 from any phone to order and supply your PAC code.
Wait 1 working day
O2 will process your PAC code and your number will transfer from Three to O2 within 1 working day. You will get a text from O2 confirming when the switch will happen. On the transfer day, your Three service will end and your O2 SIM will become active with your old number. There will be a short gap in service, typically no more than a couple of hours.
Transfer Cut-off Times: Submitting your PAC code before 5:30 PM usually means your number will transfer the next working day. Submitting it after 5:30 PM or on weekends/bank holidays will add an extra working day to the process.
Final Bill: You'll receive a final bill from Three shortly after the transfer is complete. This covers your usage up to the date of the switch.
Things to Check Before Switching
Text INFO to 85075 from your Three phone to check your remaining contract term and any charges for leaving early. Review any outstanding device payments you have with Three, as these will remain payable after switching. Ensure you have backed up any content from Three services, and check that your handset is compatible with O2's network frequencies.
Different Network Coverage
Three and O2 operate on completely independent network infrastructures. O2 uses the Telefonica network, which provides solid nationwide coverage with growing 5G availability. If you have had signal issues with Three in certain areas, O2 may offer a different coverage profile. Check O2's coverage checker at o2.co.uk/coveragechecker to see signal availability in your area.
Ready to Switch to O2?
Compare the latest O2 phone deals and find the best plan for you.