RetrO is run as with the Enduro format. With 3 courses available based on navigation challenge: easy, medium and hard. Each course has four 'legs'.
Leg 1 is on the current map. Must start between 9 and 10am.
Leg 2 is on the first lidar map from 2012. Must start before 11am
Leg 3 is on the first colour map from the early 2000s. No start before 11am, last start 12pm
Leg 4 is on the original 1991 black and white map. No start before 12pm, last start 1pm.