Legal justice in Thailand has been shifted to restorative justice for reasons. But Thai law schools have not been changed to promote lawyering skill learning opportunities due to various obstacles and limitations caused by existing legal educational policies, law curriculum's structure, knowledgeable instructors, and learners' characteristics. As a result, most graduate law students have been faced with difficulties as regards not only their mediation skill capacity but also other legal skills. To solve the problem beyond the single loop learning, the study proposed the integration of knowledge management approaches, an appropriate learning theory, and serious game concept to initiate an alternative learning tool to enhance mediation skill learning. The study demonstrated the two crucial stages of game designing and experimentation to verify the potentiality of games in enhancing the knowledge and learning engagement. The outcome of such game designing and experimentation can provided both a satisfied interactive learning tool and a linkage for the flow of advocacy skills knowledge from the community of experts to law students who, sooner or later, will be their competent team workers.