Sitwaking is an adaptive sport derived from wakeboarding, targeting wakeboarders with a physical disability. Although the sport is growing each year, the accessibility level of the sport is low. Investment costs are high and existing products are targeted towards experienced riders. Relative to wakeboarding, a different setup is required to practice the sport. A sitwaker is seated in a seat, which is attached to a normal wakeboard with an aluminum frame. At the front of the board, a footpad is installed to strap the rider’s feet. The project has been set up in cooperation with the Willem Hooft Foundation. This is an organisation aimed at improving the accessibility of adapted water sports. It builds forth on a concept design for an adjustable sitkite seat, developed by Marinke Callens. For her project, she did extensive research on the ergonomic aspect of the seat, creating an anthropometric database through measuring the target group and making 3D-scans, to create the shape of the seat. By doing this, she improved pressure distribution and optimized the fit. Her project ended with a fruitful concept. The aim of this thesis is to take this concept to the next step, validating the incorporation of the research in her design. This is done by creating a design and making a working prototype of an adjustable sitwake seat for beginners with a physical disability, which is easy and quick to adjust. The switch from sitkiting to sitwaking is done to create a more controllable test environment and because the market is easier to penetrate. The end product should be used by both sitwakers and sitkiters. Furthermore, the lifespan of the seat should be extended as long as possible. This is done through a hands-on approach with several iteration cycles. This thesis is approached with the double diamond method. The classic approach consists of four parts: Discover, define, develop and deliver. The outcome of the discover and define phase brought valuable insights from extensive desk research, qualitative interviews with the target group, observations and testing comparable products. This led to a list of requirements and wishes. Through rapid prototyping and design by doing, concepts were brought to life to check for feasibility and evaluate with users. This hands-on approach resulted in valuable insights to increase the validity of the design. The result of the project is a fiberglass seat, adjustable in width and optimized for usability. Emphasis is put on minimizing the footprint and extending its life span. The seat was tested in context to ensure its usability. Optional straps are integrated to ensure the safety of use for both beginning sitwakers and sitkiters. The final design of the sitwake seat is tailored to the user, lowering the barrier to learning this new sport by decreasing the costs.