Switch from O2 to Three
Keep your phone number when you switch from O2 to Three. Here's how in 3 simple steps.
Updated February 2026
How to Switch from O2 to Three
1
Get your PAC code from O2
Text PAC to 65075 from your O2 phone. You'll receive your PAC code by text within a minute.
You can also call O2 on 202 (or 0344 809 0202 from another phone).
2
Give your PAC to Three
Sign up for a Three plan and give them your PAC code. You can usually do this online at three.co.uk/support/switching, in-store, or by phone.
3
Wait 1 working day
Your number will transfer from O2 to Three within 1 working day. You'll get a text when the switch is complete. Your old O2 contract is automatically cancelled.
Things to Check Before Switching
- Contract status — Check if you're still in contract with O2. 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 O2.
- Phone compatibility — Make sure your phone is unlocked and compatible with Three's network. Most phones sold since 2015 are unlocked.
- Coverage — Check Three coverage in your area before you switch.
Different Network Coverage
O2 uses the O2 network while Three uses Three. Coverage may differ in your area — check coverage before switching.
Ready to Switch to Three?
Compare the latest Three phone deals and find the best plan for you.