Advancing towards urban futures in which both human communities and ecosystems can thrive requires transformative change (TC). Spatial planning can serve as a backbone for inspiring and fostering the desired transformation of cities. However, to support this transformation, the challenge for spatial planning is to create unconventional plans that account for the complex trade-offs and interactions of different scenarios through participatory procedures. A promising approach for addressing this challenge is geodesign, since it couples spatial co-design with impact simulations. This paper aims to explore how, and with what effects, a geodesign process can support the co-creation of transformative urban plans that enhance biodiversity and ecosystem services while meeting urban development goals. A geodesign process was developed and deployed for a case study neighbourhood in Stockholm, Sweden. Two scenario storylines were developed: one that follows the current city plan, and another one where the most transformative elements of the plan are further emphasized. Fourteen planning stakeholders divided into three groups translated the storylines into actual land use changes and explored the impacts of the two scenarios. The study findings indicate that the geodesign process enabled participants to develop transformative plans that address housing needs while also promoting biodiversity and ecosystem services through nature-based solutions. Participants showed high perceived desirability of TC scenarios in Skarpnäck but were mostly sceptical regarding the plausibility and probability of future implementation. Changes in perceived plausibility, desirability and probability comparing before and after the geodesign process were minor, with some inter-group variation. We recommend practical applications of geodesign to strategically involve key stakeholders throughout study conceptualization, scenario development, and model generation for better consideration of context. Enhancing geodesign tools for userfriendliness is also crucial. We suggest geodesign research to focus more on understanding its impacts on participants as well as scaling up for addressing complex challenges in metropolitan and landscape planning.