This paper was designed to investigate the application of an online inquiry-based program to European tourism from an epistemological perspective. Fifty tourism students (n = 50) participated in this study and their epistemological beliefs were measured with the Epistemological Belief Scale. A set of pre-, post-, and delayed tests were utilised to assess each participant's learning outcomes. The results showed that online inquiry-based learning (IBL) did change the participants' epistemological beliefs significantly, with a large effect size (Cohen's d) of 0.83. However, correlation analyses indicated that the relationship between an individual's epistemological beliefs before and after the online IBL experience, and the differences of pre- and post-tests, is rather low (? = 0.287). Yet, the association between their changed epistemological beliefs and the delayed test was higher (? = 0.556). These results suggest the possible effectiveness of online IBL in helping tourism students' develop more sophisticated epistemological beliefs, which may not be able to help learners comprehend the subject matter immediately but may facilitate better long-term retention.