SK Telecom announced that it will introduce SIM card formatting on Monday to address security concerns following a hacking incident that led to the leak of users' SIM card information.

The nation's leading mobile carrier made the announcement on Sunday amid a shortage of replacement chips, explaining that the method prevents illegal SIM card cloning by modifying certain SIM card data instead of requiring a full replacement.

According to the carrier, altering specific data ensures that even if someone obtains leaked SIM card information and attempts cloning, system access remains blocked.

SK Telecom emphasized that the USIM formatting will have the same effect as a physical replacement while minimizing inconveniences such as app reconfiguration and data backup.

As of 12 a.m. on Sunday, one-point-43 million customers had replaced their SIM cards, while seven-point-22 million remained in the queue after making reservations.