This paper captures the design of a crossover Augmented Reality (AR) gamified learning experience called GreenDesigners focused on sustainable engineering education for high school students. Located at a solar demonstration house, our design leverages the functionality of an Augmented Reality interface developed to coordinate learning of sustainable engineering design concepts and practices across real-world (informal) and classroom settings (formal). It is anticipated that such “seam-ful” crossover learning and assessment designs could enable a preparatory transition from informal, active learning activities to formal design-focused activities thus expanding learning opportunities for youth within STEM fields.