Oxbow lakes are iconic fluvial landforms found in the floodplains of meandering rivers around the world. Their formation is associated with meander cutoff, a process that excises sections of river channel to optimise the downstream transmission of water and sediment. After termination, sedimentary plugs form at either end of the abandoned channel to isolate it from the mainstem. Overbank floods and conveyance through tie channels maintains some hydrological connectivity, but lakes are generally considered to passively infill until they become terrrestrialised. Here, a suite of 64 lakes across two meandering rivers in the Bolivian Amazon are used to demonstrate the hydrological dynamism of oxbow lakes after cutoff by quantifying interannual variations in lake water surface area (WSA) and the mechanisms controlling them. The results suggest that WSA variations are controlled by proximity to the active channel, with the magnitude of these variations being set by mechanisms of connectivity. Lakes connected by tie channels experienced WSA changes up to 3.9 times larger than lakes with no visible connection mechanisms. Incursion lakes displayed similar WSA changes to those with tie channels, while isolated lakes were found furthest from the mainstem and had the smallest range of WSAs. Chute-lakes experienced a wider range of WSAs and were more strongly controlled by mainstem proximity than neck-lakes. An understanding of the processes governing oxbow lake hydrodynamics is important for forecasting nutrient and contaminant fluxes as well as the sensitivity of riparian wetlands to changes in catchment hydrology associated with climate change and flow modification.