Collaborative serious games have proven to have the potential to support joint knowledge construction, and there is a growing interest in applying such games to promote high-level learning. However, most of the existing studies have focused on the effects of functional, task-specific support while ignoring the social aspects of collaborative learning. This study is one aim to fill in the knowledge gap in order to understand how learners experience educational games as a means of social interaction and collaboration. The findings indicated that the game environment facilitated and supported players' socio-emotional processes by eliciting students' social presence and sociability. This has been further shown to play an important role in the emergence of social interaction and collaborative learning. These results can be applied in the design of collaborative educational games that support social aspects of collaborative learning.