Abstract Aim The aim of this study was to examine if simulating an unknown competition terrain with the computer game Catching Features improved orienteers performance in the real terrain compared to a terrain they had not simulated. Method This study examined the effect of simulation by asking elite level orienteers to simulate an unknown terrain with a computer programme for approximately one hour per day, for six days prior to an orienteering test. The participants were divided into two matched groups and one group simulated one forest terrain while the other group simulated another forest terrain. On the test day the participants ran one course in each forest terrain, in a crossover-type design. Results This study shows that simulation of an unknown terrain did not statistically significant increase an orienteers performance, however it had a small effect on orienteering and navigational performance indices. The use of simulation also had a large impact on how well the participants felt they prepared for the race. Conclusions Although simulation of an unknown terrain increases an orienteer’s self-rating of prior knowledge of the terrain, there was no clear improvement in race performance. Terrain simulation had a small effect on navigational performance, possibly at the cost of a slower running speed. This may have been as a result of an increased awareness of the difficulty to relocate in the terrain after simulation, which may have prompted orienteers to try to follow a more detailed terrain model to avoid navigational errors. Following a more detailed model may have cost them as much time as they gained from not making mistakes and this resulted in no change in race performance. In the flat terrain that was tested there were not many challenging route choices and it was not possible to detect any effect on the route choice performance by simulation.