Symptoms
- Phone displays 'SIM locked, enter PUK code'
- Entering the regular PIN no longer works
- Message appeared after a few failed unlock attempts
- Phone won't proceed past the PUK screen
Likely causes
- CommonToo many incorrect SIM PIN entriesMost SIMs lock into PUK mode after 3 wrong PIN attempts as a security measure.
- PossibleSomeone else (like a child) tried entering PINs on the phoneThis is a common cause when the phone was left unlocked or handled by someone else.
- PossibleOld or unknown default PIN causing repeated failuresSome SIMs ship with a default PIN that differs from what's assumed.
What to do
- Stop guessing PUK codes randomly, since too many wrong PUK entries can permanently block the SIM.
- Find your PUK code through your carrier's account portal, app, or by calling customer support and verifying your identity.
- Enter the PUK code exactly as given when prompted on the phone.
- When prompted, set a new SIM PIN you'll remember, or disable the SIM PIN requirement if your phone allows it.
- If the phone says the SIM is permanently blocked after too many failed PUK attempts, contact your carrier for a SIM replacement.
When to call a pro
If the SIM becomes permanently blocked after failed PUK attempts, contact your carrier for a free or low-cost replacement SIM with the same number.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.