Coastal freshwater wetlands (CFWs) are increasingly vulnerable to habitat degradation driven by land loss, hydrological modification, and salinity intrusion. These systems support diverse faunal assemblages whose biodiversity is threatened as salinity exposure intensifies. Amphibians are generally intolerant of saltwater, with elevated salinity negatively affecting their survival, development, and overall physiological condition. Because of this sensitivity, amphibians have strong potential to serve as indicators of saltwater intrusion in coastal wetlands. Two-toed Amphiuma (Amphiuma means) are large, fully aquatic salamanders endemic to the southeastern Coastal Plain. Although cryptic, they function as important mid-trophic consumers, feeding on crayfish, invertebrates, and small vertebrates while serving as prey for larger predators. A. means populations occur on three of Georgia’s barrier islands, where they are spatially isolated and face heightened risk of salinization through land-use change, storm-surge inundation, and atmospheric salt deposition. Increased exposure to high-salinity conditions may lead to differential fitness between coastal and mainland populations. This study evaluated potential differences in the physiological response of A. means from barrier-island and mainland populations when exposed to acute salinity stress. Individuals from both groups were subjected to elevated salinity treatments within an intermittent flow-through respirometry system to quantify cutaneous respiration rates and blood plasma osmolality. Preliminary analyses indicate that cutaneous respiration and plasma osmolality exhibit similar response patterns across both 5‑ppt and 10‑ppt exposures, suggesting that A. means may possess a capacity to regulate respiratory and osmotic function under acute salinity stress. This work provides novel insight into the physiological tolerance of A. means and enhances our ability to anticipate how coastal amphibian populations may respond to future environmental change in imperiled freshwater ecosystems.