SK Telecom to halt new sign-ups next week as part of USIM data breach measures

May 2, 2025

SK Telecom Co. said Friday it will suspend new subscriber sign-ups starting next week as part of its efforts to enhance customer protection services following a recent company network data breach.

“From May 5, our 2,600 retail stores will halt new subscriptions and focus on replacing universal subscriber identity module (USIM) cards,” Chief Executive Officer (CEO) Ryu Young-sang said in a press briefing.

“The suspension will remain in place until we establish measures to address the USIM supply shortage.”

The move came a day after the government issued an administrative guidance order instructing SK Telecom to pause new sign-ups until it resolves a shortage of USIM cards and stronger measures are implemented to protect customer data.

SK Telecom, the largest mobile carrier in South Korea with 25 million subscribers out of a population of 50 million, detected a cyberattack on April 18 and discovered signs of a large-scale leak of customers’ USIM data.

To prevent possible damage, the company is offering free USIM chip replacements to all of its customers, but replacement services have faced disruptions due to a limited supply of USIM cards and high demand from concerned users.