This article proposes ‘Thinking with the Archipelago’ as a critical analytical lens to examine racialized urban ecologies and spatial politics in Cartagena, Colombia. Grounded in long-term ethnographic research along the Ciénaga de la Virgen, Cartagena’s largest urban wetland, this study explores how local communities negotiate socio-ecological marginalization amid colonial continuities, green gentrification, and speculative urbanism. Drawing on Caribbean thought, Black geographies, and urban political ecology, I conceptualize the “Archipelago City” as a relational, dynamic space shaped by water, mangroves, and dispossession. This spatial metaphor challenges binary logics of center and periphery, instead foregrounding fragmented but interconnected urban geographies. Using the historic eviction of the neighborhood Chambacú as a symbolic and discursive anchor, I trace how racialized displacement and environmental degradation continue to shape urban imaginaries and technocratic development projects. In dialogue with local resistance practices, especially community-led environmental organizing in Comuna 6, I show how everyday experiences of the mangrove become forms of counter-cartography, asserting alternative ecological futures and modes of belonging. Rather than treating nature as a neutral backdrop for development, ‘Thinking with the Archipelago’ centers the poetics and politics of relational space, reclaiming the value of wetland lifeworlds. This approach decenters technocratic narratives and illuminates how communities articulate knowledge and solidarity across fragmented geographies. Ultimately, this article calls for a critical rethinking of urban-environmental futures in the Caribbean, emphasizing how colonial and neoliberal orders are actively contested through situated, everyday practices of resistance and care.