This paper aims to describe the process of constructing and implementing a governance model for a mangrove ecosystem located along two waterways within a touristic city (Cartagena de Indias, Colombia). This city has symptoms of rapid and unplanned urbanization, weak governability, and social exclusion. All of those factors were considered when the governance model was developed. During its implementation, three stakeholders negotiated in good faith until a sustainable productive project was identified. This project fits well with the characteristics of the mangrove ecosystem and the city. The model is structured around six strategies within three lines of action. A list of measurable indicators is also proposed to quantify the effectiveness of the model during its implementation. Finally, caveats and key challenges to the model’s implementation are further discussed.