What Is a PUK Code and How to Find It
What Is a PUK Code?
A PUK code (Personal Unblocking Key) is an 8-digit security code used to unlock your SIM card after you have entered the wrong SIM PIN three times in a row. When your SIM is locked, you cannot make calls, send texts or use mobile data until you enter the correct PUK code.
Every SIM card has a unique PUK code that is assigned by your network provider when the SIM is created. It is not something you choose yourself — it is a fixed code tied to your specific SIM.
When Do You Need a PUK Code?
You will be asked for your PUK code when:
- You have entered the wrong SIM PIN three times and your SIM has locked itself.
- You have set a SIM PIN and forgotten it.
- Someone else has tried to use your SIM and entered the wrong PIN.
Your phone will display a message such as "SIM locked — enter PUK code" or "SIM card PUK locked".
How to Find Your PUK Code
Check the Original SIM Packaging
Your PUK code is printed on the plastic credit-card-sized holder that your SIM card came in. If you still have this card, the PUK is usually on the back alongside the SIM serial number. This is the quickest way to find it.
Find Your PUK Code by Network
| Network | How to Find PUK |
|---|---|
| EE | My EE app (under SIM settings), or call 150 from another phone |
| Vodafone | My Vodafone app, text PUK to 8888 from another Vodafone phone, or call 191 |
| O2 | My O2 app (under My Device), or call 202 from another phone |
| Three | My3 app, or call 333 from another phone |
| giffgaff | Log in to giffgaff.com and go to SIM settings under your account |
You will need to verify your identity when requesting your PUK code over the phone. Have your account details or security password ready.
How to Enter Your PUK Code
- When your phone displays the PUK prompt, enter the 8-digit PUK code.
- You will then be asked to create a new SIM PIN. Choose something memorable but not obvious — avoid 0000 or 1234.
- Confirm the new PIN by entering it a second time.
- Your SIM will unlock and you can use your phone as normal.
What Happens If You Enter the Wrong PUK?
Warning: You have a maximum of 10 attempts to enter the correct PUK code. After 10 incorrect attempts, your SIM card is permanently locked and cannot be recovered. You will need to contact your network to request a replacement SIM card through a SIM swap.
If you are unsure of your PUK code, do not guess. Use one of the methods above to retrieve the correct code before entering it.
Tips to Avoid PUK Lockouts
- Write down your SIM PIN and store it somewhere safe (not on the phone itself).
- Keep the original SIM packaging in a drawer at home or in the office.
- If you manage business devices, record PUK codes centrally as part of your device inventory.
- Consider disabling the SIM PIN if security policy allows — go to Settings > Security > SIM Lock on most phones.
Managing SIM cards across a business fleet? Connection Technologies handles provisioning, eSIM setup and SIM swaps for your entire team. Get a free quote or call 0333 015 2615.
