The Waste4Soil project is focused on developing sustainable, cost-effective fertilizing products from recycled biowastes sourced from local food industries. By recycling food processing residues (FPR) into soil improvers (SI), Waste4Soil aims to reduce environmental impacts while enhancing food security across Europe. The project’s main objective is to create viable pathways for recycling biowastes within a circular, regional, and systemic framework that involves all actors in the food chain, thus closing essential nutrient, organic matter, and water loops. The Waste4Soil approach is implemented through Living Labs (LL) established in seven EU countries: Hungary, Finland, Spain, Greece, Italy, Poland, and Slovenia. These LLs facilitate experimentation in real-life settings, engaging key stakeholders—such as food industry representatives, waste managers, fertilizer manufacturers, commercial farms, and citizens—in collaborative activities that emphasize “show me” and “ready for practice” demonstrations of best practices. Through this co-creative approach, LLs aim to provide practical examples of sustainable waste-to-fertilizer applications that are regionally adaptable and environmentally beneficial. Central to achieving Waste4Soil’s goals is the active involvement of diverse stakeholders at every stage of the project. From co-creating solutions to participating in planning, demonstrations, dissemination, and further demonstration phases, each actor plays a critical role. The project promotes ecosystem-based collaboration among farmers and their networks, food industries, waste management companies, fertilizer producers, research and educational institutions, local and regional authorities, and civil society. By fostering these collaborations, Waste4Soil aims to develop ecosystem solutions that improve FPR management practices, making soil improvers economically viable, environmentally sustainable, and socially acceptable, thereby advancing the circular economy in agriculture.