A SIM PIN is different from your iPhone passcode. It protects the physical SIM or eSIM line, and too many incorrect guesses can lock the SIM and require a PUK code from the carrier.
Unlock a SIM that is asking for its PIN
- When the SIM PIN prompt appears, enter the SIM PIN only if you know it.
- If the PIN is accepted, the cellular line should become available.
- If the SIM is already locked and asks for a PUK code, stop guessing.
- Contact the wireless carrier that issued the SIM and request the correct PUK or SIM-unlock assistance.
- Enter the carrier-provided information exactly as instructed.
Do not try common PINs or random PUK numbers. Repeated incorrect entries can permanently disable a SIM, forcing you to obtain a replacement or new eSIM.
If your goal is to change the SIM PIN rather than recover a locked SIM, look in the cellular settings for the line’s SIM PIN controls. The wording can vary with the carrier and whether the iPhone uses one or multiple cellular lines.