For the first few decades the race was 20 km long. In 1987 a shorter distance of 10 km was added, and two years later another addition was made, this time an easy 7 km course which is suitable for children and beginners. The 50 km race has been on the program since 2004.
The most successful Fossavatn athlete is the local skier Kristjan Rafn Gudmundsson, who won the race 12 times in the 1960s and 70s. However, the skier who has participated in most Fossavatn races is another local, Sigurdur Jonsson, who first skied the race in 1938 and has participated almost every year since!
After the inauguration of the 50 km distance, Fossavatn Ski Marathon has been getting increased attention from skiers overseas. The reace was added to the FIS Race Calendar in 2005, and that same year the Fossavatn became a founding partner of the FIS Nordic Ski Marathon Cup, a series which includes the Holmenkollen Skimaraton in Norway, Tornedalsloppet in Sweden, Oulun Tervahiihto in Finland and Fossavant Ski Marathon in Iceland.
Many superstars from the world of cross-country skiing have graced the Fossavatn with their presence. The first of those was Norwegian Paul Gunnar Mikkelsplass, who skied the Fossavatn in 1985, when he was at the peak of his carreer as a world cup skier. In recent years this group has gown bigger with the addition of people such as the Norwegian legends Thomas Alsgaard and Hilde G. Pedersen, Suzanne Nyström and Lina Anderson from Sweden, and the tripple Vasaloppet winner Oskar Svärd.