A 100 km ultramarathon along the South Downs Way National Trail, typically covering the western portion of the route. The course follows rolling chalk hills across open countryside with steady climbs and descents rather than sustained ascents. Underfoot conditions are mostly firm trail and grass, with exposed sections on ridge tops. Aid stations are positioned along the route in accordance with organiser logistics.

• Other races at the same event:
South Downs 100 Mile UK Ultra
South Downs 50K Ultra Marathon