Darwin's mangrove ecosystems, some of the most extensive and biodiverse in the world, are part of the urban fabric in the tropical north of Australia but they are also clearly at risk from the current scale and pace of development. Climate motivated market-based responses, the so-called 'new-carbon economies', are one prominent approach to thinking differently about the value of living infrastructure and how it might provide for and improve liveability. In the Australian context, there are recent efforts to promote mangrove ecosystems as blue infrastructure, specifically as blue carbon, but also little recognition or valuation of them as green or urban infrastructure. Drawing on observational and qualitative analysis of semi-structured interviews, this study examines how key stakeholders in Darwin frame and understand mangroves in relation to the urban, and how they are anticipating and responding to governance efforts to frame mangroves and pay for their carbon sequestration and storage services as blue carbon. The push for large infrastructure development and an expanding urban footprint, present serious challenges for mangrove protection, and the study evidences both denial and complacency in this regard. However, although the concept of blue carbon is already taking effect in some circles, it was not viewed as straightforward or as appropriate by all study participants and may very well work in practice to exclude groups within the community. Both clear governance problems, as well as unrecognized and vernacular community connections to mangroves in Darwin, indicate that there are ongoing conceptual and empirical challenges to be considered in recognizing and valuing mangroves as part of urban life.