The tourism industry faced a turning point due to the COVID-19 pandemic. This study examined potential tourists' behavior change during the pandemic. In-depth interviews with 14 potential tourists who planned to travel abroad in 2020 but delayed their plans were conducted. The collected data was analyzed using NVivo 12. Coding of the interview data resulted in 143 concepts and 31 sub-categories divided into nine categories. To be specific, the causal condition was the “outbreak of the pandemic.” The contextual conditions included “social distancing” and “travel alert.” The phenomenon was “limited tourist activity.” The intervening conditions were “tourism nostalgia”, “need for tourism”, and “perceived risk.” The actions/interactions included “tourism response behavior in the pandemic.” The consequence was “changes in tourism behavior.” In the selective coding stage, the core category was found to be “change in tourism behavior according to tourist responses in the pandemic.” The results provide a theoretical framework for understanding the psychological mechanisms and behaviors of potential tourists in the pandemic. Moreover, new factors related to changes in the tourism behavior of potential tourists. The study confirms recent research findings that the psychological mechanisms of tourists are an even greater influence than the pandemic itself. This study contributes in-depth understanding of the perceptions, attitudes, behaviors, and reactions of potential tourists in the pandemic situation, which was previously insufficiently explored.