The 2021 World Triathlon Duathlon Championships was a duathlon competition held in Avilés, Spain from 6 to 7 November 2021 and organized by World Triathlon.
The Elite and U23 races consisted of a 10.65 km (6.62 mi) run, 39.6 km (24.6 mi) bike and 5.2 km (3.2 mi) run.
The championship also included other races per age group, junior, sprint per age group and para-duathlon.
[1] In the women's Elite race, Venezuelan Joselyn Brea, competing under World Triathlon flag, won her first world championship.
French Nathan Guerbeur won his second consecutive title in the men's Elite edition.