To evaluate the association between COVID-19 incidence among high-school athletes participating in different indoor winter sports and attending schools with in-person versus virtual instructional delivery. Cross-sectional survey. US high schools. High-school athletic directors. Indoor winter sports, school instructional delivery method, and state COVID-19 incidence. Surveys were distributed to high-school athletic directors throughout the United States regarding sport reinitiation and COVID-19 cases in winter 2020 to 2021. Separate mixed effects Poisson regression models were developed to evaluate the associations between reported COVID-19 incidence and (1) different sports and (2) school instructional delivery method, while adjusting for the background, state COVID-19 incidence. Four hundred thirty schools had restarted fall sports, representing 31 274 athletes on 1404 teams from 14 states. One thousand four hundred sixty cases of COVID-19 were reported, representing a case rate of 4668 cases per 100 000 athletes and an incidence rate of 58.7 cases per 100 000 player-days. Reported COVID-19 incidence was greatest among girls' hockey (82.1 cases per 100 000 player-days (95% CI, 56.8-115) and boys' hockey [76.7 (61.8-94.2)] and lowest among swimming [39.0 (31.1-48.2)] and gymnastics [28.5 (13.1-54.2)]. No difference in reported COVID-19 incidence was identified among athletes attending schools with virtual versus in-person instruction [incidence rate ratio = 0.86 (0.52-1.4)]. In this nationwide survey of US high-school athletic directors regarding indoor winter sports, reported COVID-19 incidence was lower in noncontact sports but unrelated to school instructional delivery method. This information may help guide decision-making regarding high-school sport participation during the COVID-19 pandemic.