Adunako Mendi Duatloia is a sprint mountain duathlon held in Aduna, a small town in Gipuzkoa, Spain’s Basque Country. The race hub is at Herriko Plaza. This is an afternoon event, usually starting at 15:00, following the classic run-bike-run format: a short mountain run, a mountain bike section, and then another short mountain run.
The course is compact yet steep, offering a genuine mountain race feel. It begins with 3.66 km on foot, including 118 metres of climbing. This transitions to a 14.5 km mountain bike segment with 541 metres of climbing, concluding with a 1.83 km run featuring an additional 59 metres of ascent. Lokatzetan Kirol Taldea and Adunako udala are noted in the race organization records, and the event is part of the Euskadiko Triatloi Federazioa calendar. One edition was designated the Basque Championship, lending the small-town race a more significant competitive profile than its distances might imply.