The Irako Triathlon takes place in September around Cape Irako in Tahara City, Aichi Prefecture, featuring a sea swim, a bike leg, and a run. It has been held annually in September since 1987. The event now provides three distances: Type A middle distance at 90.25 km, Type B standard distance at 53.5 km, and Type C sprint distance at 18.75 km. Participants begin in rolling waves of 20 people, starting 10 seconds apart, with distinct morning starts for each distance.
The swim portion is centered at Coconut Beach Irako. The cycling course crosses Irako, Nishiyama, Nakayama, and Konakayama. The run follows the Tahara Toyohashi Cycling Road, also known as the Atsumi Cycling Road, through Irako, Hiide, and Horikiri. Type A is designated for registered triathlon association or university league members and contributes to the age-group national long-distance series. Types B and C are accessible without such membership, with Type C being a recent addition as the sprint option. The race proceeds in rain if conditions permit, but organizers reserve the right to shorten distances, modify the course, or cancel if weather poses safety risks.