Exergames enable users to utilize computer applications to engage in exercise. The literature on exergames has revealed their effects on users’ physical indicators. However, insufficient research has examined the predictors of user intention to play exergames. We examine these predictors through an approach grounded in flow theory. Conducting a longitudinal study, we asked participants to play exergames for a total of 18 hours in 12 weeks. We find that a strong perceived challenge and its interaction with performance-approach goals are positively related to user intention to play exergames. We contribute to the literature by providing a novel predictor of user intention to play exergames that can be exploited to encourage the use of exergames. We also provide exergame providers with insights into designing exergames to induce users’ playing behaviour.