Protect your phone with a screen-lock passcode and your SIM with a PIN
Your SIM is the small card that receives text-message verification codes. If you lose your phone, someone may move the SIM to another handset, receive those codes and reset your accounts. A SIM PIN requires a code when the card starts up in another phone, cutting off that route.
What it takes
Free. Set up each code once.
What you may gain
After a phone is lost, moving its SIM to another handset can be a quick way to receive the owner’s verification texts. Those codes can then be used to reset accounts one by one. A PIN-protected SIM cannot receive them in the new phone until it has been unlocked.
Context & considerations
Look for “SIM lock” in your phone’s settings. Initial PINs are often 1234 or 0000, but three wrong attempts will require the carrier’s PUK code to unlock the SIM. Check your carrier’s instructions rather than guessing, and write down the PIN securely when you set it.
Research & references
Practical experience; no direct research reference.