Potential tourists may project their upcoming travel in two directions of mental time travel: from the present to the posttravel future, and from a mentally simulated posttravel future back to the present. Based on regulatory focus theory, this study examined the matching effect of the mental time travel direction and tourism activity type on tourist intention, as well as the mediating role of tourist expectation. The results show that for challenging (relaxing) tourism activities, mental time travel from the future back to the present (from the present to the future) is more effective in stimulating potential tourists’ travel intentions. Tourist expectations mediate this process. This study advances the theoretical application of mental time travel in tourism research and offers practical implications for the marketing of tourism activities.