The travel bubble program presented an appealing strategy for reopening international travel safely. However, a full vaccination regime is the foremost prerequisite of the program. Therefore, vaccination and the travel bubble are inextricably linked. This study investigated the roles of perceived vaccine efficacy, attitude towards the COVID-19 vaccine, and attitude toward the travel bubble on travel bubble intention. More importantly, the study also examined the mediating role of hope and fear among unvaccinated Korean adults between 20 and 29 years old. A total of 535 samples were collected to test the proposed conceptual model using structural equation modeling. In general, the results supported the proposed hypotheses. Notably, the intention to travel to a bubble destination was explained by 57% of the variance. Furthermore, hope mediated the relationship between vaccine attitude and travel bubble intention. Whereas fear mediated the relationship between perceived vaccine efficacy and intention. Hence, the findings suggest doubts around the vaccine efficacy and that a positive attitude towards the vaccine also install hope among the research samples.