Recent advances in water purification technology, the combined pressures of population growth and climate change, depletion of traditional water sources, and rising cost of water, have together improved the cost-effectiveness and market competitiveness of large-scale seawater desalination as a major water source option for water stressed cities around the world. Uptake of this technology has accelerated correspondingly in the past decade or so. Touted as a ʻsilver bulletʼ solution for offering a drought-proof and inexhaustible source of potable water, the lifeblood of cities, desalination represents a fairly radical shift in the geographies and political ecologies of urban water, but it is a change that has, as of yet, been somewhat overlooked in the critical geography literature. This dissertation aims to make a small contribution towards rectifying this oversight, by offering a critical analysis of desalination using an urban political ecology approach. It does so in three phases. First, by building a conceptual framework through review of relevant literature. Here, the flow of water from sea to land is conceptualised as: (1) flows of nature; (2) flows of money; and (3) flows of power. Second, a methodological approach appropriate for researching the political ecology of seawater desalination is proposed. An argument is made for a synthesis between Marxist historical materialism and Actor Network Theory (ANT), one that combines the political potency of the former with the reflexivity and analytical nuance of the latter. Third, theoretical conceptualisations of desalination are grounded in an empirical analysis of a specific case study, that of Tampa Bay in Florida. Despite having a high annual rainfall and abundant ground and surface water resources, much of Florida is considered to be water stressed, making the Sunshine State the nationʼs leader in the development and implementation of desalination technology. This final phase frames desalination using the same nature-money-power structure, which is used to conceptualise this technology in terms of its implications for environment and development in Florida.