Mercury (Hg) contamination in the Amazon is well-known globally and well-studied. However, there remains a notable research gap regarding Hg contamination in the coastal zone and continental shelf of the Amazon region. Therefore, the aim of this study was to evaluate the levels of Hg concentrations in water and sediments within the coastal region and continental shelf of the Amazon, identifying spatial trends and the main geochemical processes that influence the transport and fate of this metal in the area. The Hg concentrations in the unfiltered water varied among the analyzed regions (p <
0.0001), with the highest values recorded in the estuary of the Pará River, 13.8 pmol L