Societal challenges such as climate change and health inequalities require complex policy decisions, for which governmental organizations rely on a good information position. Having access to data from various domains is seen as a facilitator of making evidence-informed decisions that are more legitimate and less uncertain. To identify and make data available that is stored at various organizations, stakeholders participate in sociotechnical networks, also known as data ecosystems. Data ecosystems aimed at addressing societal challenges are characterized as complex because knowledge about societal issues is uncertain, information is scattered among (governmental) actors, collaboration extends beyond existing organizational networks, and values and interests of network actors can be conflicting. In this translational article, we examine how to successfully establish and maintain data ecosystems aimed at addressing societal challenges, given these complexities. We analyze two cases of successful data ecosystems in the Netherlands and present five narratives about how these data ecosystems navigated these complexities. We find that establishing collaboration among network actors, using bottom-up approaches, contributed to the success of both cases. The cases created structures in which participants were able prioritize the right questions, find common interests, and work together. The narratives present insights for government officials about collaboration in data ecosystems and add to the literature by highlighting the importance of organizational capabilities.