See if the phone is carrier locked

The status lives in settings or on the carrier account. A different SIM is the honest test.

1. 01

   iPhone: Settings → General → About. Look for Carrier Lock. No SIM restrictions means it is unlocked.

2. 02

   Android: Settings → Connections or Network → SIM manager, or the carrier app. Wording varies by brand.

3. 03

   Insert a SIM from another carrier. If it registers, the phone is not network locked.

4. 04

   If it asks for an unlock code, stop and request the official unlock from the carrier that sold the line. Do not buy a code from a stranger.

Official carrier and settings procedures only. This is not a bypass, IMEI, or stolen-phone service.