Designing collaborative three-dimensional learning games for vocational learning may be one way to respond to the needs of working life. The theoretical vantage points of collaborative learning for game development and the "design-based research" methodology are described; these have been used to support collaborative learning in the vocational context. The aim of the empirical study is to determine, firstly, what kinds of design elements were essential from the point of view of the collaboration, and secondly, what kinds of discussions students engage in during the game. In this study, three essential features of design elements stood out. Firstly, the scripted tasks have to require true collaboration. Secondly, curricular-specific learning tasks are essential. And, finally, it is beneficial if the game design addresses aspects of vocational work in a manner that would not be possible in traditional classroom settings. Furthermore, this study indicates that groups engaged in shared collaboration in which students actively provided information and asked questions. (Contains 2 figures and 3 tables.)