This article investigates the energy intensity and related impacts of the Eastern Route of China's South-North Water Transfer Project, based on the concept of the water–energy nexus. It finds that from November 2013 to May 2017 a total of 2.35 billion kWh of energy was consumed to transfer 15.5 billion m3 water driven by a large-scale system of pumping stations. This energy production required 7.4 million m3 of virtual water and emitted 1.93 MtCO2e of carbon. An average water–energy nexus ratio of 0.05% indicates that transferring 100 m3 of water consumes 0.05 m3 of virtual water due to the electricity consumption of the Eastern Route's pumping stations. It is estimated that to transfer 7.3 billion m3 water by 2030, this mega project will consume 1.35 billion kWh of energy, 4.6 million m3 of virtual water and emit 0.94 MtCO2e of carbon. These findings and scenario analysis demonstrate that strategies are needed for mitigating the energy intensity of the Eastern Route, such as improved pumping efficiency, reduced water loss during water delivery, decreased water quotas, and promotion of other, less carbon-intensive water sources in destination provinces.