With issues like climate change, pollution, deforestation, drought, extreme weather patterns, and a world population that is projected to reach 9.8 billion by 2050, there has been a strong push in industrial design education to teach sustainability to the next generation of designers. In order to teach sustainability, many schools utilize hands-on projects as an engaging way for students to learn and apply design principles but many of the materials used for the project prototypes are often not sustainable or eco-friendly including blue/pink insulation foam, high-density urethane foams, foam board, MDF, particle board, putty fillers, plastics, epoxies, adhesives, joint compound, primer, and non-eco-friendly paints. Is there a way to teach sustainable design effectively using only sustainable or more eco-friendly prototyping materials? This paper describes a case study where a 2nd year industrial design studio was tasked with designing and building a personal watercraft made only from corrugated cardboard (no tape, glue, paint, or fasteners) which had to transport the student across 75 ft. (width of a pool) of water without sinking. The successes, failures, and learning outcomes are shared with the hope that others would build upon this learned experience.