Sea level rise (SLR) is a threat to coastal environments, with the inundation of seawater into freshwater aquifers leading to contamination of groundwater, making it unsuitable for drinking and irrigation. The rising ground water level further results in increasing risk in pluvial, fluvial, and groundwater flooding. Despite the importance of understanding the impacts of SLR on groundwater systems over coastal regions, current Earth system models (ESMs) commonly ignore the exchanges of water, sediments, and materials at the land-ocean interface. We developed a new land-ocean hydrologic coupling scheme in the Energy Exascale Earth System Model (E3SM) to simulate water exchange at land-ocean interface driven by SLR-induced inundation and assessed the corresponding impacts on coastal groundwater at global scales. Seawater infiltration is found to be the dominant mechanism of the land-ocean coupling, while the lateral subsurface flow exchange is much smaller. Our results show that SLR-induced seawater infiltration will raise groundwater levels, enhance evapotranspiration, and increase runoff with distinct spatial patterns globally in the future.