In learning based on socio-scientific issues, teachers primarily use role playing in situation learning to promote students’ knowledge and responsibility and to teach them how to reach a consensus in multirole scenarios. However, if participants only engage with the material from the perspective of having one role, they will ignore comprehensive information on said issue. Therefore, the roles students play during multirole situational learning lead to diversity biases in learning results. To help participants enhance their competencies related to issues and eliminate learning gaps, we developed an issue-based board game named Water Ark based on the following four design ideas: multirole simulation, reflective goal, systemic situation, and interactions of society. The results indicated that after playing the game, participants’ knowledge and responsibility regarding water resource adaptation improved significantly. Furthermore, the findings revealed that the gap between the learning outcomes of participants with different roles in the game was not statistically significant, except in terms of students’ personal willingness to act. Thus, these design ideas could improve the utility of board games for learning about socio-scientific issues with multirole scenarios.