Switch from Three to O2
Keep your phone number when you switch from Three to O2. Here's how in 3 simple steps.
Updated February 2026
How to Switch from Three to O2
1
Get your PAC code from Three
Text PAC to 65075 from your Three phone. You'll receive your PAC code by text within a minute.
You can also call Three on 333 (or 0333 338 1001 from another phone).
2
Give your PAC to O2
Sign up for a O2 plan and give them your PAC code. You can usually do this online at accounts.o2.co.uk, in-store, or by phone.
3
Wait 1 working day
Your number will transfer from Three to O2 within 1 working day. You'll get a text when the switch is complete. Your old Three contract is automatically cancelled.
Things to Check Before Switching
- Contract status — Check if you're still in contract with Three. You can switch at any time, but you may need to pay an early termination fee if your minimum term hasn't ended.
- Outstanding balance — If you're paying off a handset, you'll need to settle any remaining balance with Three.
- Phone compatibility — Make sure your phone is unlocked and compatible with O2's network. Most phones sold since 2015 are unlocked.
- Coverage — Check O2 coverage in your area before you switch.
Different Network Coverage
Three uses the Three network while O2 uses O2. Coverage may differ in your area — check coverage before switching.
Ready to Switch to O2?
Compare the latest O2 phone deals and find the best plan for you.