The eastern equatorial Pacific Ocean (EEP) plays a critical role in the global climate system. Widespread CO2 outgassing and cooler than average sea surface temperatures (SST) associated with the Pacific cold tongue occur in this region due to its persistent upwelling driven by the easterly trades driving Ekman suction at the surface; and strong natural variability associated with the El Niño-Southern Oscillation (ENSO) which affects the variability of weather globally. This study analyzes the mean seasonal and interannual ocean mixed layer heat budget of the EEP including the Galápagos Cold Pool and an open-ocean equatorial region in the western EEP in a 140-year present day control simulation of a high-resolution version of CESM 1.2 (0.1° ocean). These two regions are significant in that both experience significant upwelling; however, the latter is an order of magnitude smaller due to differing mechanisms. Galápagos upwelling is driven by open-ocean Ekman suction velocity, but also via topographic obstruction of the Equatorial Undercurrent (EUC) by the islands. We diagnose the relative contributions of each term within the heat budget, with particular emphasis on vertical advection, entrainment, and eddy diffusion—processes that are especially important near the Galápagos Islands themselves. A thorough understanding of these processes and their contribution to the surface heat balance is essential in understanding both the formation of the Galápagos Cold Pool, and how it may respond to future climate change with implications for this climatically and ecologically vital region.