You know you have a SIM lock if a different carrier's SIM card prompts an error message or your phone only shows one network in settings; for iPhones, check Settings > General > About > Carrier Lock, where "No SIM restrictions" means unlocked, while Androids often show network lock status in Settings > Connections/Network & Internet > Mobile Network > Network Unlock or by checking if you can manually select other providers in network operators. The most definitive test is swapping a friend's SIM from a different carrier to see if it works.
Visit our Carrier Unlock Guide to contact your carrier for help on checking your device's status.
Enable or Disable SIM PIN Lock on Android Smartphones
You can also find your SIM card's PIN number on its original packaging.
The only way to unlock a password-protected SIM is to get a special code called a PUK (PIN unlock key) from your mobile provider. The provider may need you to prove your identity to give you this code. This wikiHow teaches you how to use a PUK to unlock your SIM card.
SIM Lock Code Location Your PUK code is typically found on your SIM packaging or can be obtained from your carrier. Default SIM Unlock PIN Most SIM cards have a default PIN of 1234, which can be reset using a PUK if entered incorrectly multiple times.
This lock restricts the phone to using only that carrier's SIM card, preventing you from switching to another wireless carrier. Carriers often use SIM locks as an incentive for signing contracts. They offer a phone at a discounted price or an attractive payment plan, but lock you in for a certain period.
Here's the reality: Android phones don't have universal secret codes that magically unlock devices without deleting data. As "codes such as *2767*3855# or ##7780## trigger a factory reset" according to EaseUS, most "secret codes" just wipe your phone. That's why knowing these legitimate recovery methods matters.
If you're going through your carrier: Gather Your Information: Have details ready such as your account number and IMEI number (you can find this in Settings > General > About). Request Unlocking: Follow their procedure—this could be filling out an online form or calling support directly.
Typing *#0*# (star-hash-zero-star-hash) into the phone dialer on a Samsung device opens a hidden General Test Mode, a secret diagnostic menu used for checking hardware components like the screen (touch, color), sensors, speakers, cameras, and vibration. It's a valuable tool for users to self-diagnose issues or verify a device's functionality, especially when buying a used phone, as it allows you to test functions like touch responsiveness, RGB colors, and sensor accuracy.
A PUK (Personal Unlocking Key) is an 8-digit code that unlocks your SIM if the PIN has been entered incorrectly three times.
To protect your SIM card or eSIM from others using it for phone calls or mobile data, you can use a SIM PIN. Then every time you restart your device or remove the SIM card, your SIM card or eSIM will be locked automatically and you'll see “Locked SIM” in the status bar.
*#7353#: This code opens the Quick test menu. This allows for a quick way to test certain aspects of your Android.
You can unlock your phone for free by requesting it through your carrier—most major U.S. providers like T-Mobile, AT&T, and Verizon offer free unlocking once your device is paid off, active for a required time, and not blacklisted. Use your IMEI number to check unlock eligibility and follow the carrier's instructions.
*#2663# Dial this code and, in the window that opens, click on 'Refresh WiFi Version. ' This will slightly improve your phone's WiFi performance!
For Android devices
Select 'Network Operators' or 'Mobile Networks'. If your device allows searching for and selecting different network operators, it's likely not SIM-locked. If only one carrier shows up on your phone, it's probably locked to that carrier. To use a different carrier, you need to unlock your phone.
If you forgot or don't know your SIM PIN
It will always be 1234 unless someone has manually changed it. A Personal Unlocking Key, or PUK code, allows you to reset your SIM card's PIN number, after you've entered an incorrect PIN three times.
Android
Carriers are required to unlock your phone free of charge after you've fully paid for the device (or coughed up an early termination fee), according to the Federal Communications Commission. It can often be handled by your carrier remotely, allowing you to skip a trip to the store.
If you enter your PIN (Personal Identification Number) code incorrectly several times, the SIM card is locked.