Nearly 1 million users switch mobile carriers in May in wake of SKT data breach

A record-breaking 933,509 South Koreans switched mobile carriers in May, nearly doubling the five-year monthly average, following a major SIM card data breach at SK Telecom (SKT). Most of the defections favoured KT, which gained nearly 200,000 former SKT users—five times the typical volume. The breach, first reported in April, triggered a steady exodus, with LG U+ and MVNOs also seeing significant gains. Prior to the incident, user migration between carriers had remained stable at around 500,000 per month. SKT has since offered free SIM replacements and boosted device subsidies to stem the loss.