What happens when you enter the wrong PIN too many times (Three)
| Step | Action | What It Fixes |
|---|---|---|
| 1 | Check Three network status | Confirms if issue is network-wide |
| 2 | Toggle aeroplane mode on/off | Re-registers SIM on Three network |
| 3 | Restart your phone | Clears temporary network errors |
| 4 | Check Three APN settings | Fixes incorrect data configuration |
| 5 | Re-insert SIM card | Fixes poor SIM contact issues |
| 6 | Contact Three support | Resolves account or SIM faults |
A PUK (Personal Unblocking Key) code is an 8-digit code used to unlock a SIM card that has been blocked after too many incorrect PIN attempts. If you enter your Three SIM PIN incorrectly three times in a row, your SIM will become blocked and you will see a message asking for your PUK code. Entering the wrong PUK code ten times will permanently destroy the SIM.
Finding your PUK code on Three's app or website
Your Three PUK code can be found in several ways without having to call customer service:
1. Three account online: Log in to your Three account at the Three APN hub. Go to your SIM or account details section — the PUK code is usually listed alongside your SIM information.
2. Three app: Open the Three app and go to your account or SIM settings. Your PUK code should be visible in the SIM details section.
3. The SIM's original card mount: many networks print the PUK directly on this credit-card-sized holder.
4. Call Three customer service: If none of the above options work, call Three and ask for your PUK code. You will need to verify your identity. See the Three APN hub for the correct number.
SIM safety checklist
Get the PUK from the account or SIM packaging rather than guessing, which risks a permanent lock
Entering the PUK code correctly on Android and iPhone (Three)
When your phone displays SIM card locked — enter PUK code, type the 8-digit PUK code on the unlock screen. You will then be asked to set a new 4-digit PIN of your choice. Enter the new PIN twice to confirm. Your SIM will immediately unlock and reconnect to the Three network.
SIM safety checklist
Get the Three PUK from your account or SIM packaging; guessing permanently locks it
Creating a new PIN after PUK entry (Three)
Turning off the SIM PIN altogether is possible through Settings → Security → SIM Card Lock, or it can be changed to a memorable one there — a trade-off of security for avoiding lockouts.
Entering the wrong PUK code (How to Get Three PUK Code)
You have ten attempts to enter the correct PUK code. After ten incorrect attempts, the SIM is permanently blocked and cannot be recovered. You will need to order a free replacement SIM from Three — your phone number and account will transfer automatically to the new SIM.
SIM safety checklist
Take the PUK from Three's account portal or the packaging rather than guessing