Non-formal learning is becoming increasingly important in everyday life. Both the availability of open online learning opportunities and the number of participants in online courses continue to grow. Initially learners report high levels of motivation, but completion rates tend to be low. In the present study, we examined motivational trajectories of learners completing a non-formal online course. To this end, 450 learners of 49 open online courses offered by Bavarian universities completed up to three online questionnaires throughout the course. First, we used latent profile analysis to explore motivational trajectories within five subtypes of situational motivation, which resulted in four different motivational profiles. However, all profiles were characterized by remarkable stability over time, and differences only in the actual levels of the five motivational subtypes. Second, we used bivariate latent change score models to focus on differences of change in intrinsic motivation when analyzing simultaneously with situational interest. In addition, we considered self-regulation and mastery goal orientation as predictors of change in motivation. For intrinsic motivation there was only a small mean change and compensating effect from T1 to T2. We discuss the findings in the light of the fact that there are high dropout rates in non-formal online courses and offer practical advice on how to better address non-completers in future research.