Welcome to Boston’s Only Triathlon! We are thrilled to have you join us in one of the greatest cities in the world for a weekend of events.


Our mission at ethos is to bring athletes together for challenging and unique sporting events in cities worldwide.

Our team works year round to inspire and attract triathletes from Boston and around the globe to participate in world-class events like the Boston Triathlon.


Participants will swim Boston’s historic Dorchester Bay, bike its city streets and run along Southie’s scenic shoreline. The course is spectator-friendly, easy to get to and has ample parking.

Mark your calendars and make this year’s Boston Triathlon a highlight of your summer. Whether you’re testing your stamina, supporting a cause, touring the city or cheering on friends, Boston’s one and only triathlon welcomes you to the city.