BACKGROUND: As Japan undergoes population aging, nursing care workers play an important role in supporting older adults in the community, which has been particularly critical during COVID-19 pandemic. However, the knowledge, attitudes, and practices (KAP) among nursing care workers regarding COVID-19 have not been fully elucidated. METHODS: A self-administered questionnaire survey was conducted in June 2020 among 481 nursing care workers in the nursing care facilities in Aichi, Japan. We assessed COVID-19-related KAP scores of nursing care workers, and compared them by age, sex, and years of experience. RESULTS: A total of 481 nursing care workers responded to the survey. Out of a maximum of 10 points, the mean (standard deviations) knowledge, attitude, and practice scores were 6.86 (1.45), 7.11 (1.42), and 7.40 (1.89), respectively. Comparisons between the KAP scores revealed significantly higher knowledge scores among older workers (p < 0.001) and significantly higher knowledge scores (p = 0.002) and practice scores (p = 0.033) among workers with more than 20 years of working experience. CONCLUSIONS: The findings revealed that older age and a longer duration of experience were associated with higher COVID-19-related knowledge and practice scores. To better support older adults, it is essential to improve the education system for care workers and to provide environments for delivering necessary information rapidly.