ABSTRACT Personal nostalgia can potentially contribute to tourists' subjective vitality and wellbeing, yet extant studies have seldom examined how it happens. This study adopts a mixed‐methods approach to uncover the transmission mechanism. Through qualitative interviews ( N = 12), the study found that existential authenticity is the underlying power that triggers one's personal nostalgia and links it with positive emotions and subjective vitality. A questionnaire survey ( N = 407) further tested and confirmed this relationship in addition to the positive impact of personal nostalgia on wellbeing. Moreover, positive emotions, subjective vitality, and existential authenticity are found to mediate between personal nostalgia and tourist wellbeing. The study contributes to the existing knowledge of personal nostalgia by revealing how personal nostalgia enhances tourist wellbeing directly and via the mediation of positive emotions, subjective vitality, and existential authenticity. Practically, the findings provide useful references for destination marketers in deploying effective strategies to attract repeat tourists.