Chemical fluxes from groundwater to inland and marine coastal waters are controlled by complex transport and reaction processes occurring within nearshore aquifers. Waves are an important forcing mechanism that can modify hydraulic gradients and mixing conditions in nearshore aquifers, affecting the fate of chemicals and their discharge to coastal waters. Variable wave conditions may drive redox changes that mobilize geogenic chemicals, including the toxic metalloid arsenic. Once mobilized, these chemicals may enter coastal waters, posing risks to human and ecosystem health. This study aims to investigate the influence of variable wave conditions on arsenic mobilization in a nearshore aquifer and determine the timing and magnitude of potential hot moments of arsenic release to coastal waters. This was addressed by developing a MODFLOW/PHT3D groundwater reactive transport model to simulate the effects of variable wave conditions on arsenic geochemistry and transport. The model was based on extensive field data collected at Little Beach, Lake Erie, Ontario. Simulations show that changes in wave height alter groundwater flows, driving redox shifts that change arsenic concentrations. The wave-induced geochemical changes promote episodic release of arsenic from minerals in the aquifer. Although some mobilized arsenic is sequestered onto newly formed iron oxides, field data and simulations suggest that high wave periods may trigger hot moments of arsenic release to coastal waters. This model provides an improved understanding of how waves may regulate arsenic mobilization and arsenic fluxes to coastal waters. This information is needed to refine coastal chemical budgets and support ecosystem risk assessments.