One discussion in the context of education for sustainable development centers around the importance of suitable teaching materials for promoting pro-environmental attitudes. Especially applications that let learners travel to otherwise difficult to reach places seem promising for digital sustainability education that is both accessible and socially just. Applications for German-speaking learners are however rare, and it has often not been checked whether those that exist are fit for classroom use. Therefore, this paper focuses on an investigation of the Virtual Reality (VR) learning application "On Biodiversity's Tracks", developed by greenpeace, with a focus on the environment of the Amazon rainforest. In an experimental study, (1) VR-based and (2) traditional lesson conditions were compared in terms of their effects on self-appraisal of knowledge, interest, and attitude. Pre- and post-questionnaires were used to uncover between-subject and within-subject effects. 172 students at eight secondary schools in Germany were recruited. The results revealed that both experimental conditions were effective regarding increase of self-appraised knowledge. An increase in interest was barely found in either condition. Changes at the attitudinal level could mostly not be discovered. Further analyses highlighted that, unlike the experimental conditions, there were significant differences in self-rated learning outcomes between the types of schools. In general, our results indicate that VR learning applications can contribute to the teaching of topics such as sustainability and biodiversity in a target group-oriented and meaningful way. However, further research is needed to adequately assess VR learning effectiveness, especially regarding affective learning outcomes, due to their importance for sustainable behaviors of subsequent generations.