A SIM swap moves a phone number to a different SIM or eSIM. In a criminal SIM swap, someone convinces or tricks the carrier into making that change without your permission. They may then receive text verification codes and password-reset calls meant for you. This does not automatically give them your phone's files.
A useful example
Your phone suddenly shows no mobile service while a bank sends a text code you did not request. Check for a local outage, but contact your carrier through its official number promptly. Ask whether your number was moved and request a lock or extra account protection if available. Then review email and financial accounts for unauthorized recovery attempts.
Reduce the risk
Set a strong carrier account PIN, protect the email attached to the carrier account and prefer an authenticator app or security key over text codes for high-value accounts when offered. The
FTC explains SIM-swap warning signs. Text codes still help when they are the only option; the key is knowing their dependency on your phone number.
Practical distinction
A dead battery or local outage can also cause lost service. The urgent clue is lost service together with carrier notices, account resets or activity you did not start.
