This study investigates regional and local governmental agencies resilience in their use of risk communication with other governmental agencies. Analyses are based on the case of South Korea's response to the 2015 outbreak of the Middle East Respiratory Syndrome Coronavirus. Based on a survey of governmental organizations, the study indicates that governmental agencies seek either reciprocal or redundant communication ties with other governmental agencies while they aim to secure crucial information from high‐level organizations to tackle the transboundary nature of the infectious disease during the outbreak response. Semi‐structured interviews with South Korean officials confirm that subnational governmental agencies rely on the national government and also seek information from other regional and local agencies to improve the resilience in interagency risk communication and to prevent the further transmission of the infectious disease in their local jurisdictions. This study empirically demonstrates how governmental agencies cope with the uncertainty of infectious disease transmission by expanding risk communication channels when hierarchical communication channels and information systems do not meet the needs of outbreak response. The research findings contribute to the understanding of the interactions across organizations in addressing the needs of public health crises that are transboundary in nature and provide important lessons for outbreak responses in South Korea as well as in other countries.