Check your phone settings for a carrier lock or network lock status
Insert a SIM card from a different carrier and see if it connects
Look for a “SIM not supported” or “Invalid SIM” message
Call your current carrier and ask if the phone is unlocked
Use your carrier’s online account or device status page if available
Check the phone’s IMEI on your carrier’s unlock status tool
On iPhone, go to Settings, General, About, and look for Carrier Lock
On Android, check Settings, Network, or SIM settings for lock information
Test mobile data, calls, and texts with another carrier’s SIM
Review your purchase receipt or account records for unlock confirmation