Ultra-trail running and walking are sporting activities where human endurance is tested and pushed to its limits. In studying the expressions of the endurance experiences of ultra-trail runners and walkers, this paper discloses how ultra-trail practices require more than just physical endurance. Besides examining ultra-trail practices, the research also unpacks the notion of endurance itself. This paper then positions ultra-trail running and walking as analytical lenses to explore the contemporary meanings and values of endurance and what this can tell us about the contemporary societal context in which these activities take place. Drawing upon ethnographic fieldwork in Belgium, including participant observation, interviews, visual data, and digital data, this paper argues that endurance, as cultivated and developed in ultra-trail running and walking, extends beyond leisure pursuits to become a form of capital with implications for wider social contexts. By offering an ethnographic account and analysis of ultra-trail running and walking, the research addresses the gap in anthropological literature regarding endurance and ultra-trail practices. Furthermore, the paper aims to advance our understanding of endurance and its social significance.