SK Telecom restarts eSIM subscriptions after data breach

SK Telecom, a major mobile carrier in South Korea, will partially resume new eSIM subscriptions this week after halting services due to a nationwide data breach.

The breach, discovered on April 18, 2025, involved unauthorized access to data from USIM cards, prompting the company to replace affected cards for free.

New subscriptions will restart in physical stores on June 16, 2025, with full eSIM service resuming after June 20, 2025.

The Ministry of Science and ICT previously said full services could resume once all affected USIM cards were replaced.

Industry sources say the partial restart shows progress in completing the USIM card replacements.

🔗 Source: The Korea Times

🧠 Food for thought

1️⃣ Telecom breaches cause unprecedented customer churn and financial damage

Data breaches in telecommunications can trigger massive customer exodus, with severe financial consequences that extend beyond immediate recovery costs.

Historical analysis shows telecom customers are particularly sensitive to security incidents. For example, when SK Telecom experienced a breach in 2025, nearly one million users switched carriers in a single month, representing a significant increase over normal switching rates 1.

This customer exodus created significant financial impact, with projections showing potential losses of up to $5 billion from the combined effects of customer departures, waived termination fees, and regulatory penalties 2.

For telecommunications providers, security breaches create a devastating chain reaction. Compromised infrastructure leads to eroded customer trust, which directly translates to market share loss as customers migrate to competitors. For instance, KT Corporation gained nearly 200,000 former SK Telecom customers during one such incident 1.

This demonstrates that in the highly competitive telecom sector, security has evolved from a technical requirement to a fundamental business differentiator directly tied to customer retention and financial stability.

2️⃣ South Korea’s critical infrastructure faces persistent security challenges

South Korea’s telecommunications sector has experienced repeated high-profile infrastructure vulnerabilities over the past decade, highlighting ongoing challenges in protecting vital communications networks.

In 2011, SK Telecom’s Cyworld site suffered a major breach affecting approximately 35 million users, which investigators traced to an IP address in China 3.