As our populations become more urbanised, public green space will assume key functions in the promotion of the health and well-being of the populace. We assessed the beneficial outcomes of physical activities undertaken in Australian national parks using a questionnaire-based survey combined with GPS tracking of walkers, hikers, and runners. We estimated energy expenditure of park visitors based on GPS tracking trip data using two different estimation methods. Park visitors perceived considerable improvement in numerous health and well-being indicators; many of which increased with increasing activity levels. We found that hikers burned the greatest amount of net energy (916 kcal) as they preferred more difficult tracks with greater slopes, followed by runners (790 kcal) and walkers (450 kcal). For many walkers and hikers, physical activity was incidental to other activities such as sightseeing, socialising, and experiencing nature; such activities, thus, deserve highlighting when promoting attributes of parks and other public green spaces. GPS tracking allowed for sampling a broad population of park visitors at a participation rate of 80%, and the calculation of additional trip characteristics such as trip distance and velocity. Identifying health and well-being benefits via an inter-disciplinary approach using GPS tracking data to determine the intensity and spatio-temporal distributions of physical activity in relation to different park infrastructure is a promising area for attention to raise awareness of the direct benefits of visiting public green spaces.