Purpose – Drawn from flow theory, this study aims to explore children's flow experiences in virtual reality (VR) by examining the relationships between VR experience length, arousal and flow experience (time estimation and enjoyment). Design/methodolog/approach – A within-subject laboratory experiment was conducted using 9D VR and iMEC 12. A total of 47 children participated in this study. Both survey data and physiological data were collected. Findings – The results revealed that longer VR videos evoked lower arousal, higher respiratory rates and less enjoyment among child participants than shorter videos. This study also verified the mediating effects of respiratory rates measured arousal on time estimations and self-reported arousal in terms of enjoyment. Originality/value – This study fills a research gap related to children's flow experiences in VR, as Children's Voices remain limited in Tourism Research. The study findings offer meaningful insights for destination marketers to leverage the growth of parent-child tours and the increasing effects of VR on the tourism industry.