Background: To control the spread of the new SARS-CoV-2 infection's disease (COVID-19), appropriate precautionary behaviors by the public should be promoted. We have been concerned about the differences among countries regarding the populations' cognitional and behavioral patterns as well as attitudes toward information sources in relation to the anxiety about the COVID-19 pandemic because knowing these differences will contribute to our understanding of the patterns of epidemic-related anxiety and behaviors, and it will help optimize future policies for preventing the second wave of the epidemic.Methods: To examine the differences among countries in their residents' perception, attitude, and precautionary behaviors toward COVID-19, we conducted a cross-sectional study through an online questionnaire survey. Adults who had been registered in Cross Marketing Inc. and living in the UK, Spain, or Japan were subjected. A total of 8,000 people stratified by age were recruited on a first-come, first-served method. Knowledge of and anxiety about COVID-19, the frequency and credibility of several information sources, and the magnitude of each precautionary behavior were examined in the questionnaire on March 27–28, 2020 in Japan and April 17–21 in the UK and Spain.Results: Compared to Japan, the knowledge and anxiety level and the frequency of precautionary behaviors were higher in the UK and Spain. Participants with infected acquaintances were more concerned about COVID-19. However, participants in the UK rarely wore a medical mask. Participants in the UK and Spain were eager to get information about COVID-19 compared to those in Japan. The participants in Spain tended not to trust official information and to believe specialists' comments instead.Conclusion: The urgency of the spread of COVID-19, cultural backgrounds, and recent political situations appear to contribute to the differences among countries revealed herein.