SK Telecom has initiated a free USIM replacement service on April 28, 2025, following a serious hacking incident that compromised customer information. The company opened an online reservation system to facilitate the process, but the launch was marred by significant access issues due to overwhelming demand.
As many customers sought to replace their USIM cards, the T-World website and app faced severe connectivity problems, with users reporting delays and outages almost immediately after the service went live. By 10 AM, the T-World app displayed a 'connection delay' notice, and the website struggled to handle the influx of traffic, leading to widespread frustration among customers.
SK Telecom had anticipated high demand and urged customers to utilize the online reservation system (care.tworld.co.kr) to mitigate potential chaos at physical locations. Users are required to verify their identity before selecting a store for the USIM replacement. Despite these precautions, reports indicated that by 9:50 AM, over 53,000 users were already in the queue online.
In front of the SK Telecom T-World store in Gwanghwamun, Seoul, hundreds of customers were lined up even before the store opened, eager to secure their new USIMs. The company is providing free replacements at approximately 2,600 T-World stores and major airport roaming centers nationwide.
SK Telecom has also emphasized the importance of enrolling in its 'USIM Protection Service,' a free security feature designed to prevent unauthorized use or replication of USIM information. Customers can subscribe to this service through the T-World app or the company’s website. The service blocks all communication services if a USIM is detected in a device other than the subscriber's own phone, allowing users to quickly identify any potential breaches.
Despite these efforts, the demand for replacements has raised concerns about stock shortages. SK Telecom currently holds around 1 million USIMs and plans to secure an additional 5 million by the end of May. However, with approximately 23 million subscribers and 1.87 million users of MVNO phones relying on SK Telecom's network, the total number of eligible replacements could reach 25 million, leading to potential confusion and delays.
On the day of the service launch, many customers reported being turned away due to a lack of stock at various locations. Some had visited stores only to find notices stating that USIMs were exhausted. SK Telecom has announced that it will refund customers who replaced their USIMs at their own expense from April 19 to April 27, 2025, as a gesture of goodwill.
As the situation unfolded, SK Telecom reiterated its commitment to resolving the issues stemming from the hacking incident. The company stated, "We apologize for the inconvenience caused by the cyber intrusion and are committed to alleviating customer concerns while resolving the matter swiftly."
The hacking incident itself was identified on April 18, 2025, when SK Telecom discovered that malicious code had compromised the security of its systems, leading to the leakage of sensitive USIM information, including unique identification numbers for subscribers. While the full extent of the damage and the details of the breach are still being investigated, SK Telecom has stated that no further damage reports have been received since the incident.
As customers continue to seek ways to protect their information, the overwhelming response to the USIM replacement initiative underscores the heightened awareness and concern regarding personal data security. With ongoing efforts to enhance security measures, including a commitment to improve non-face-to-face authentication protocols, SK Telecom is taking steps to reassure its customer base.
In the meantime, customers are encouraged to utilize the online reservation system for USIM replacements to avoid long waits and ensure they receive their new cards as quickly as possible. The company has also promised to maintain adequate stock levels to meet ongoing demand.
As the situation develops, SK Telecom remains focused on providing support and solutions to its customers while navigating the challenges brought on by this significant cyber security breach.
