AbstractThe issue of the effects of travel on subjective well-being (SWB) has recently attracted increasing interest in transport studies. A common finding is that travel affects SWB indirectly through out-of-home activities. However, little is known about how to operationalize this relationship. In this study, we proposed a conceptual model and estimated structural equation models relating travel mode use and activities with multiple SWB dimensions, including affective components (positive affect and negative affect) and cognitive components (belongingness, achievement, and confidence in coping). We used data from a national mobility project in Japan (N = 13,000) to estimate the postulated models. We found that while public transport use enhanced the cognitive components of SWB, it also had a negative effect on the affective components of SWB. Car use affected SWB in a more complex pattern; it promoted SWB by enabling leisure activities but also reduced SWB dimensions of belongingness and achievement through shopping activities. Active travel modes did not have a clear effect on SWB; for example, walking to school was associated with increased belongingness, whereas walking for shopping negatively influenced belongingness. Other contributing factors, such as COVID-19 worry, car access, and the ‘going-out’ problem-solving style, were also found to influence multiple dimensions of SWB. Overall, our study showed how the effects of activities on multiple dimensions of SWB varied with different travel modes, thereby revealing the indirect effect of travel mode use on SWB via activities. Suggestions for shaping transport policies towards SWB are also discussed.