Judgment and decision skills are now essential graduate attributes for the future engineer, in particular for facing the more frequent than ever volatile, uncertain, complex and ambiguous (VUCA) world in both professional and societal situations. One of the responsibilities of engineering programs is to train students to be agile and capable of taking decisions in challenging VUCA situations. This paper presents conceptual and practical results of an European project which explored, designed and iteratively analysed innovative educational learning and teaching activities to train decision-making skills. Following a design-based research approach, including both quantitative and qualitative analysis, the four VUCA dimensions were categorized, the relevant decision skills were defined, and activities to train decision skills were tested and evaluated. One outcome of this work is a rational selection of learning activities based on experiential learning to train specific decision-making skills, which can be integrated in the engineering curriculum. These learning and teaching activities are freely available for adaption in engineering programs. In addition, six reference models are proposed and delineated, in an effort to support the integration processes for curriculum revisions.