The aim of the present study was to compare speed profiles and tactical choices between cross-country skiers on different performance levels in a mass-start cross-country skiing competition by describing the race development and individual speed profiles over the entire race and identifying differences in speed profiles and the tactical choices distinguishing skiers on different performance levels. 45 skiers were tracked with a GNSS device during a 21 km skating style cross-country skiing mass-start competition in the Norwegian Cup. Additionally, all skiers answered a questionnaire with quantitative and qualitative questions about their tactics and experiences during the race. The skiers showed an overall positive speed profile with a higher average speed in the first three laps than the average speed in the whole race (3.7 ± 1.41 %, p < .001), with reduced speed in the last part of the race. The Top 10 performing skiers showed a more even pacing pattern than groups of skiers ranked 11-20, 21-30, and 31-40, indicated by significantly less % difference between the first three laps and the whole race (p < .01 for all groups). Speed in uphill terrain was most important for overall performance (r = .964, p < .001), and speed differences between groups were largest in uphill terrain with a 2.0%, 5.5%, 6.0% difference between Top 10 skiers and groups ranked 11-20, 21-30, and 31-40, respectively, (p < .001 for all). Performance in the final sprint decided outcome within groups of skiers skiing together. The questionnaire indicated that the skiers in general planned to start as hard as the lead and keep up as long as possible. There was no pattern for performance-level differences in planned tactics between groups, but after the race, skiers ranked 1-10 to a greater extent felt that they were able to complete the race accordion to their strategies. In conclusion, while an overall positive speed profile was observed, better performing skiers showed a more even speed profile over the race. Performance in uphill is most decisive for overall performance, but the final sprint is important for the final outcome within groups of skiers skiing together. Most skiers, independent of performance in this specific race, had the tactic to follow the lead as long as possible. Higher ranked skiers were more able to implement their strategies than their counterparts.