In 2024, we brought London closer to the ocean: Nearly 700 design students at the Royal College of Art participated in the Grand Challenge 2023/24. In teams of five, the students were tasked with tackling challenges around London and the Ocean from a design perspective. The challenge involved multiple methodologies, including design engineering, speculative design, service design, materials- and fashion-related approaches. Each team had one month to develop a compelling proposal. Fifty students participating in the Grand Challenge were able to join the Extended Reality/XR Stream: Ten teams of five students each came up with different design solutions using the Unreal Engine 5. This paper presents how Unreal Engine 5 was introduced to students through lectures and hand-on sessions, and how XR technologies were employed to creatively interpret the original brief of the Grand Challenge and how it inspired our students to come up with unique design propositions. In particular, we discuss here two case studies in detail: XRiver and SuDScape. These two student projects were among the top 13 teams exhibited at the final Grand Challenge show, offering insights and recommendations for incorporating XR into design education.