The aim of the study was to investigate participation and performance trends regarding the nationality of successful finishers in single stage ultra-marathons of more than 200 km. The association between sex and nationality with running speed was investigated in ‘Badwater’ (217 km) held in North America with 208 women and 818 men and ‘Spartathlon’ (246 km) held in Europe with 206 women and 1,814 men between 2000 and 2012. In ‘Badwater’, most of the finishes were achieved by athletes from the USA, followed by athletes from Germany and Great Britain. In ‘Spartathlon’, the highest number of finishes was obtained by athletes from Japan, followed by athletes from Germany and France. In ‘Badwater’, women from USA were the fastest (7.7±0.4 km/h), followed by women from Canada (6.2±0.6 km/h). For men, the fastest finishes were achieved by competitors from the USA (8.6±0.4 km/h), followed by athletes from Mexico (8.2±1.0 km/h) and Canada (7.0±0.8 km/h). In ‘Spartathlon’, the fastest female finishes were obtained by women from Japan (9.6±0.3 km/h), followed by women from Germany (9.1±0.4 km/h) and USA (8.8±0.3 km/h). In men, the fastest finishes were achieved by runners from Greece (11.7±0.8 km/h), followed by athletes from Japan (11.4±0.4 km/h) and Germany (11.1±0.3 km/h). These results show that American ultra-marathoners dominated both participation and performance in ‘Badwater’ in the USA. In ‘Spartathlon’ in Europe, however, both female and male runners from Japan were dominating participation whereas male ultra-marathoners from Greece and female ultra-marathoners from Japan dominated performance. Future studies need to investigate participation and performance trends for Japanese ultra-marathoners in other races such as 100 km and 100 miles ultra-marathons.