Insert a SIM card from a different carrier
Check whether the phone connects to the new carrier’s network
Try making a call, sending a text, and using mobile data
Look in the phone’s settings for carrier lock or network lock status
Contact the current carrier and ask if the device is unlocked
Use the phone’s IMEI with the carrier’s unlock status checker
Reset network settings and test with another SIM if needed
Check for messages saying the SIM is unsupported or invalid
Confirm whether the phone was sold as factory unlocked
Test the phone in another country with a local SIM