This study investigated the influence of the antecedents of unplanned purchase behavior (service climate, travel attraction, in-store factors, and out-of-store factors) on the aforementioned behavior as well as the moderating effects of shopping values (hedonic and utilitarian shopping value) on unplanned purchase behavior. Questionnaires were distributed at an international travel fair and 443 valid samples collected. The results of the study are as follows: (1) Service climate, travel attraction, in-store factors, and out-of-store factors had positive influence on unplanned purchase behavior; (2) Hedonic shopping value moderated the effects of service climate, travel attraction, and in-store factors on unplanned purchase behavior; and (3) Utilitarian shopping value moderated the effects of service climate and in-store factors on unplanned purchase behavior. The results also revealed that the facility-related services provided by the international travel fair influenced visitors’ unplanned purchase behavior. Sales were promoted at the fair site, and the “invisible” services provided by first-line service personnel affected the unplanned purchase behavior of visitors in terms of buying tourist accommodation. The results confirmed that shopping value influenced service climate, and that in-store factors affected unplanned purchase behavior. Regarding limitations, the current study only analyzed travel fair consumers from Taiwan. Future studies should include travel fair consumers from other countries and cultures to increase the robustness of the current study’s results.