The design of urban public spaces is typically performed by architects and urban planners, which often only focus on the visual aesthetics of the urban space. Yet, a visually pleasing public open space designed for relaxing will be underused if it sounds unpleasant. Ideally, sonic design should be integrated with visual design, a need the soundscape approach answers. The current trend of co-creating the urban space together with all stakeholders, including local residents, opens up new opportunities to account for all senses in the urban design process. Unfortunately, architects and urban planners struggle to incorporate the soundscape approach in the urban design process and to use it in the context of co-creation. In this work, a hackathon is proposed to generate creative concepts, methods and tools to co-create the urban public space. A soundscape hackathon was organized in the spring of 2019. Participants were challenged to apply their own immersive approaches or virtual and/or augmented reality solutions on selected urban soundscapes. They presented their results to colleagues in the field and to a professional jury. This paper describes the process and results of the event and shows that a hackathon is a viable approach to accelerate the co-creation of the urban public space.