Twofold Bay marks the beginning of this event, with salt air giving way to a long journey inland and upward to Charlotte Pass via Mount Kosciuszko Summit. Established in 2004, the Coast to Kosci Ultramarathon has the character of a hard-won tradition among ultra runners, a "unique and iconic race" that is genuinely "organised by runners for runners." Its core values—Community, Humility, and Resilience—align with the demands of the course.
The route offers a genuine "sea to summit experience," traversing various climate zones before reaching the summit of Mount Kosciuszko, the highest point, and then descending to the finish at Charlotte Pass. The course involves significant climbing and equally demanding descents, requiring more than just raw fitness or road-running pace. Participation is by invitation only, with approximately 60 runners invited, creating a small field where all participants understand the challenge they have undertaken.