Approximately 40% of the global population lives within 100 km of the coast, and many coastal communities rely on fresh groundwater resources that are increasingly threatened by climate change. Canada’s Atlantic coast is particularly vulnerable, with the highest projected rates of relative sea-level rise in the country, combined with a disproportionately high number of residents who drink groundwater. Rising seas and intensifying coastal storms force landward migration of saline water (or saltwater intrusion, SWI) into previously freshwater zones. The resulting shifts in salinity or redox conditions can cause geogenic contaminants to be mobilized and thereby become a source of metals in groundwater. The objective of this study is to investigate the links between SWI and metal contamination of coastal groundwater. Rainbow Haven beach (Nova Scotia) is a provincial park with chronic arsenic contamination in their groundwater supply. To investigate the drivers of arsenic mobilization, various field methods are being employed including monitoring of groundwater level, temperature, salinity, oxidation-reduction potential, metal concentrations, and geophysical surveys between the ocean and dune interior. Geophysical surveys reveal a distinct freshwater lens that is 3 m thick and varies seasonally. Coastal-aquifer interactions are evident as ocean tidal signals manifest in the groundwater piezometers, and elevated groundwater levels occur following coastal storms. Additionally, redox gradients exist both vertically and laterally across the saltwater-freshwater continuum. This research is still in the early stages but will benefit water users through a new understanding of interrelations between coastal forcing, hydrogeology, and geochemistry in an era of unprecedented climatic change.