TREE PLANET, established in 2009, offers a new model of a social enterprise, pursuing a social goal via a smart phone application. The TREE PLANET app is a mobile game whose objective is for players to plant and grow virtual trees, which are directly linked to real-world afforestation. The purpose of this study is to introduce this innovative social venture business model. Theoretically, this case study provides a model of internalizing positive externality by reducing transaction costs in afforestation. In practice, TREE PLANET is considered a new business model in the social venture field. Therefore, TREE PLANET represents an illustrative case of a social enterprise based on an innovative business model.