As climate change progresses, there is increasing emphasis on net zero and energy system decarbonization. Several technologies are contributing to this agenda, but among these, the growth of solar photovoltaics has consistently exceeded all projections. With increasing land-use pressures, and the expense of building-mounted photovoltaics, water surfaces are increasingly being exploited to host these technologies. However, to date, we lack an understanding of the global potential of floating solar photovoltaics and, as such, we do not yet have sufficient insight to inform decisions on (in)appropriate areas for future deployment. Here we quantify the energy generation potential of floating solar photovoltaics on over 1 million water bodies worldwide (14,906 TWh). Our analysis suggests that with a conservative 10% surface area coverage, floating solar photovoltaics could produce sufficient energy to contribute a considerable fraction (16%, on average) of the electricity demand of some countries, thus playing an important role in decarbonizing national economies.