Worldwide, most global cities are located in coastal zones, but a paradox of sustainability is especially striking for American global cities. This article examines such paradox drawn between globalization-induced development and coastal ecosystems. It focuses on two developmental components found principally in global cities: (1) the agglomeration of foreign waterborne commerce and global business services and (2) the accelerated activity and mobility habits of a global professional class. Despite formidable gaps in research, some anecdotal evidence suggests unique hazards exist for the coastal ecology as globalization pressures expand a global city’s urban footprint.