BackgroundThis study examined participation and performance trends in ‘Ironman Hawaii’ regarding the nationality of the finishers.MethodsAssociations between nationalities and race times of 39,706 finishers originating from 124 countries in the ‘Ironman Hawaii’ from 1985 to 2012 were analyzed using single and multi-level regression analysis.ResultsMost of the finishers originated from the United States of America (47.5%) followed by athletes from Germany (11.7%), Japan (7.9%), Australia (6.7%), Canada (5.2%), Switzerland (2.9%), France (2.3%), Great Britain (2.0%), New Zealand (1.9%), and Austria (1.5%). German women showed the fastest increase in finishers (r2 = 0.83, p < 0.0001), followed by Australia (r2 = 0.78, p < 0.0001), Canada (r2 = 0.78, p < 0.0001) and the USA (r2 = 0.69, p < 0.0001). Japanese women showed no change in the number of finishers (r2 = 0.01, p > 0.05). For men, athletes from France showed the steepest increase (r2 = 0.85, p < 0.0001), followed by Austria (r2 = 0.68, p < 0.0001), Australia (r2 = 0.67, p < 0.0001), Brazil (r2 = 0.60, p < 0.0001), Great Britain (r2 = 0.46, p < 0.0001), Germany (r2 = 0.26, p < 0.0001), the United States of America (r2 = 0.21, p = 0.013) and Switzerland (r2 = 0.14, p = 0.0044). The number of Japanese men decreased (r2 = 0.35, p = 0.0009). The number of men from Canada (r2 = 0.02, p > 0.05) and New Zealand (r2 = 0.02, p > 0.05) remained unchanged. Regarding female performance, the largest improvements were achieved by Japanese women (17.3%). The fastest race times in 2012 were achieved by US-American women. Women from Japan, Canada, Germany, Australia, and the United States of America improved race times. For men, the largest improvements were achieved by athletes originating from Brazil (20.9%) whereas the fastest race times in 2012 were achieved by athletes from Germany. Race times for athletes originating from Brazil, Austria, Great Britain, Switzerland, Germany, Australia, Canada, Japan, New Zealand and France decreased. Race times in athletes originating from Australia and the United States of America showed no significant changes. Regarding the fastest race times ever, the fastest women originated from the United States (546 ± 7 min) followed by Great Britain (555 ± 15 min) and Switzerland (558 ± 8 min). In men, the fastest finishers originated from the United States (494 ± 7 min), Germany (496 ± 6 min) and Australia (497 ± 5 min).ConclusionsThe ‘Ironman Hawaii’ has been dominated by women and men from the United States of America in participation and performance.