Objectives: No study has yet analyzed risk factors to determine whether students withconfirmed coronavirus disease 2019 (COVID-19) infections may affect students at neighboringschools. Therefore, this study aimed to determine risk factors for COVID-19 transmission among schools within a community in the Republic of Korea. Methods: An epidemiological investigation was conducted among 696 students and schoolstaff members at 3 schools where COVID-19 clusters began on October 15, 2021. Interviews, visithistory surveys, a facility risk assessment, and closed-circuit television were used to identifyrisk factors. The statistical significance of risk factors was also evaluated. Results: We confirmed 129 cases (18.5%) among the individuals exposed to COVID-19 at the 3schools, many of whom had a history of visiting the same multi-use facilities. The odds ratioof having visited multi-use facilities such as karaoke rooms was 1.90 (95% confidence interval, 1.03–3.50); the number of visits to a karaoke room and the visit durations were significantly higher among confirmed cases than non-confirmed cases (p = 0.02 and p = 0.03, respectively). Conclusion Having a history of visiting karaoke rooms often and spending a long time there were risk factors for COVID-19 infection and inter-school transmission. Thus, it is necessary to investigate the status of multi-use facilities frequently visited by adolescents and consider incorporating them into the scope of school quarantine to prevent infectious diseases at schools in a community.