In the early stages of the Covid-19 pandemic, South Korea was often hailed for its success in taming the spread of the virus through the use of ICT technologies that facilitated rapid tracing and notification of those who had encountered individuals who had tested positive. In this essay for the “Covid-19 and the Social Sciences” series, Myungji Yang traces the development of disease prevention infrastructures in South Korea following lessons learned from experiences with earlier epidemics, showing how changes in both technology and law played important roles in its strategy. Yang also raises questions about the impact of the intrusive surveillance systems on individual privacy and freedom of movement.