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More than 200,000 SKT users replace USIM chips on first day of hacking-prompted replacement service

Published: 29 Apr. 2025, 09:17

People line up outside an SK Telecom store in Mapo District, western Seoul, on April 28. [JOONGANG ILBO]

More than 200,000 subscribers of SK Telecom, Korea's biggest mobile carrier, received new universal subscriber identity module (USIM) chips on Monday, the first day of the company's offering of a free replacement service following a recent network hacking incident.

Some 230,000 completed their USIM chip replacement, and 2.63 million had made online reservations for the service as of 6 p.m., according to SK Telecom.

The company opened a webpage for the service at 10 a.m., with around 2,600 SK Telecom stores nationwide also starting the replacement service at the same time.

Some 25 million SK Telecom subscribers, including nearly 2 million budget phone users, are eligible for the replacement service, according to SK Telecom.

SK Telecom plans to provide new USIM cards by verifying customers' ID cards and reservation confirmation texts during on-site replacements.

However, shortly after the system went live, SK Telecom's official website and the USIM replacement page became difficult to access due to heavy traffic. Offline stores also reported long lines of customers waiting for the service.

The shortage of USIM cards is expected to persist for some time, as SK Telecom currently holds about 1 million units. The company said it plans to secure an additional 5 million cards by the end of next month.

On April 18, SK Telecom detected signs of a massive leak of customers' USIM data due to a cyberattack.

"We apologize once again for causing inconvenience to our users due to the cyber hacking incident," the company said, vowing to do its "best" to swiftly resolve the situation.

The Personal Information Protection Commission (PIPC) Chairman Ko Hak-soo said during a session at the National Assembly that an investigation into the incident could potentially take up more than a year.

The PIPC has been communicating with SK Telecom on the situation and has launched a task force to handle the matter, Ko added.

To prevent secondary damage, consumers can change their USIM chips or may consider switching their mobile carrier, Ko said.

"With the revision of the [personal information protection] law two years ago, which strengthened punishment clauses, there lies a possibility of a considerable level of punishment," he said, noting the PIPC will recommend SK Telecom to devise additional measures to relieve concerns over the hacking incident.

Yonhap