The implementation of open data policies requires the efforts of many public employees across different levels of government, who may be unaware of the benefits and risks of open data. Serious games have demonstrated potential for training in a professional environment. For this research, a collaborative digital serious game about open data was developed. A sample of 24 civil servants played the game. Pre-test and post-test surveys were used to evaluate the effects of the game on participants’ perception of open data. Likert score changes between pre-test and post-test indicated that the game had a positive effect on the willingness to share public sector data. By simulating the setting of a public office and by having players make decisions about whether to open certain datasets, the game facilitated learning about the benefits and disadvantages of opening data.