Port cities face enormous sustainability challenges. In this chapter, we propose a relational view of these challenges and explore how different models of governance connect the three pillars of sustainable development: Economy, environment, and society. We also address the contradictions inherent to new port plans or waterfront projects, zooming in on the case of Lisbon, Portugal to evaluate the role of heritage in the sustainable development of its historic maritimewaterfront.We assess the extent to which reusing heritage structures strengthens the Lisbon port-to-city relationship with regard to governance and outcome. Our account shows that the city departed from its earlier object-based approach to adopt UNESCO’s approach of Historic Urban Landscapes (HUL). This shift has triggered deeper reflection among key city actors on the connections between city and port in Lisbon, as well as on the role of the waterfront landscape. We argue that its new approach to heritage potentially produces new governance arenas where new port-city coalitions can emerge—coalitions that have the potential to align economic and environmental objectives with the sociocultural motives that underpin the goals of heritage preservation. We conclude by emphasizing both the challenges of public participation and the critical importance of engagement of port authorities. Each is necessary if European port cities are to effectively pursue sustainable relationships.