A staff member demonstrates the "SIM card reset" service, which allows partial information changes without replacing a physical SIM card, at a SK Telecom store in Seoul on May 12. Yonhap News

“There are 450 people ahead of me for a SIM card replacement, so I’ll have to wait even longer.”

On the morning of May 12, Ms. A, 69, dropped by a T World store in Jongno-gu, Seoul, on her way to the gym, just in case. But she quickly turned around because the line for SIM card replacement was still too long despite her reservation. “My husband and son, both SK Telecom users, switched mobile carriers after the recent hacking incident,” she said. “Since I don’t use online banking for large sums, I haven’t switched it yet.” Asked whether she was considering the “SIM card reset” service, which reportedly has the same effect as a replacement, she replied, “I won’t feel safe unless I physically change the SIM card.”

A staff member at the T World store said, “At our location, about 80 percent of customers choose to replace their SIM cards, while 20 percent opt for the SIM card reset service to avoid the hassle of re-registering financial certificates and services.”

As of May 12, SK Telecom officially introduced a SIM card reset option, which does not require replacing a physical SIM card. It also upgraded its system to allow overseas roaming users to subscribe to the “SIM Protection Service.” However, ongoing customer anxiety and disappointment over SK Telecom’s insufficient initial response have led to a surge in customer defections, which may negatively impact the company’s future earnings.

SK Telecom plans to automatically enroll overseas travelers and residents who are not already subscribed to the SIM Protection Service by May 14. Existing customers will be covered without needing to sign up again.

During a daily press briefing, SK Telecom emphasized, “Subscribing to the SIM Protection Service alone can 100 percent block illegal SIM card cloning.”

Customers who want to reset their SIM cards are still frustrated that they end up having to wait for their turn after making a reservation for a SIM card replacement.

A home visit service is being prepared for customers in areas without T World stores. However, SK Telecom said that mailing SIM cards is procedurally complicated and will be decided carefully.

As of midnight on May 12, 1.47 million SK Telecom users had replaced their SIM cards. An additional 7.21 million customers were waiting in line to do so.

Meanwhile, SK Telecom reported that its revenue for the first quarter of this year fell 0.5 percent year-on-year to 4.45 trillion won and operating profit rose 13.8 percent to 56.74 billion won. The company's performance was driven by growth in its artificial intelligence (AI) businesses, including AI data centers, but the second quarter will reflect the impact of the hacking crisis.

While SK Telecom acknowledged that SIM card replacement costs, customer churn, halted new sign-ups, and potential regulatory fines could negatively affect its financials, it said the full impact was difficult to estimate at this stage.

“It is confirmed that the number of customers who have moved their numbers to other mobile carriers has increased more than usual,” said Yoon Jae-woong, head of SK Telecom's marketing strategy division, in a conference call. Regarding when new subscriber sign-ups would resume, he said, “SIM card supply is expected to stabilize by mid-May, and with the introduction of the SIM card reset option, we expect to process the SIM card replacement demand more smoothly. We will discuss resuming sign-ups with relevant government departments.”

SK Telecom CFO Kim Yang-seop said, “Although this incident will inevitably have a negative impact on our financial results, we believe the key to restoring corporate value is to invest fully in protecting our customers and regain trust as quickly as possible.”