Coastal ecosystems are at risk of microbial contamination from anthropogenic sources such as wastewater discharges and agricultural runoff, which may introduce pathogenic and antimicrobial-resistant organisms (AROs). Rising sea temperatures may influence their survival, potentially exacerbating public health risks in recreational waters. This study investigated the impact of temperature on the survival of clinically significant carbapenemase-producing E. coli (CPE) in artificial seawater (ASW) and natural seawater (NSW).  Microcosm experiments involved inoculating seawater with 10⁵ CFU/100 mL of CPE and incubating samples at temperatures ranging from 11.0–29.8°C, reflecting predicted median and maximum temperatures for current and future timepoints across Northern and Southern Europe. Survival was assessed at 0, 24, 48, and 72hrs using the Colilert®-18 system (IDEXX). Two strains, NDM-5 and OXA-48-producing E. coli recovered from Irish seawater, were tested in ASW, while only NDM-5 was evaluated in NSW due to experimental limitations.  Both strains demonstrated temperature-dependent declines in survival. At lower temperatures (11–14.8°C), bacterial survival was prolonged, with ~13–15% of NDM-5 and ~11–13% of OXA-48-producing-E. coli remaining viable in ASW, and ~3–9% of NDM-5 in NSW, by 72 hours. At 29.8°C, survival decreased sharply to <1% in ASW and NSW. While similar trends were observed, decay was faster in NSW. These findings highlight the influence of temperature and environmental conditions on CPE survival in seawater. Cooler conditions may prolong microorganism survival, increasing potential public health risk. Understanding these dynamics is essential for managing AROs in coastal ecosystems under changing climatic conditions.