While in Flatwater Racing events, paddlers race on a straight course, Marathon Racing involves paddling sleek racing craft over long distances, on either the flatwater of lakes, and dams, or the flowing water of a river. Traditional Marathon Racing competitions, like ICF World Cup and World Championships, involve a fixed flatwater course with regular portages, where the paddler must carry the canoe or kayak. Each race lasts approximately 3 hours.

Many popular marathons are raced down sections of river, where the paddler must negociate the currents, rapids or weirs, or else portage around these obstacles. Some of these events attract over 2000 athletes each year and are often run inseveral stages over several days.