<p>Experiential avoidance is highly correlated with Internet addiction among college students, but the underlying mechanisms between these variables require further exploration. This study aims to elucidate the psychological mechanisms linking experiential avoidance and Internet addiction by examining depression as a mediating factor and physical activity as a moderating factor. A self-report survey was conducted among 1,506 college students from Chinese universities. The survey included measures of experiential avoidance, Internet addiction, depression, and physical activity. Descriptive and correlational analyses were performed on these variables, and a moderated mediation model was constructed. Experiential avoidance showed significant positive correlations with both Internet addiction and depression among college students, while physical activity was significantly negatively correlated with these variables. Depression partially mediated the relationship between experiential avoidance and Internet addiction, and physical activity moderated the relationship between experiential avoidance and depression. This study further clarifies the psychological mechanisms underlying the relationship between experiential avoidance and Internet addiction among college students. Depression serves as a mediator in this relationship, whereas physical activity can attenuate the strength of the relationship between experiential avoidance and depression. These findings underscore the potential of incorporating physical activity into mental health interventions, offering a dual approach to alleviate depression and reduce Internet addiction risk among college students. Moreover, this research provides actionable insights for policymakers and practitioners in designing strategies that promote both psychological well-being and healthy behaviors.</p>