Tourism is the primary source of income for many countries, particularly developing ones. However, due to the impact of the 2019 Coronavirus epidemic, the tourism sector has been significantly affected. This study aims to identify factors that influence motivation and travel frequency. Two scenarios were compared: during COVID-19 and post-COVID-19. The questionnaire was developed based on the Health Belief model. The data collection process involved distributing a comprehensive questionnaire throughout Thailand, with the aim of achieving a fair and balanced representation of respondents from six distinct regions: northern, central, eastern, western, north-eastern, and southern. The study included a total of 2100 participants. Twenty hypotheses were formulated to analyze the relationship between the latent constructs. Factor analysis and Structural Equation Modeling were utilized to analyze the data from the questionnaires. The results from SEM found that the model was consistent with the empirical data. The model of the during COVID-19 pandemic had three supported hypotheses, namely H2d, H5d, and H9d, which were the correlation between tourism motivation and perceived severity, self-efficacy, and outcome expectations, respectively. In the post-COVID-19 pandemic period, seven hypotheses, including H1p, H2p, H3p, H4p, H5p, H9p, and H10p, supported the correlation between intention and perceived susceptibility, perceived severity, perceived benefits, perceived barriers, self-efficacy, outcome expectations, and frequency. The support for H10p indicated that stimulated motivation could lead to behavioral changes and increase people’s travel frequency. This study proposes policy recommendations and public relations guidelines to encourage more frequent travel.