This study investigates the statistics of extreme sea levels (ESLs) along the northwest coast of Ireland. We focused on the combined effects of storm surges, semidiurnal high tides, and projected relative mean sea level rise under two climate scenarios (RCP 4.5 and RCP 8.5) for the 21st century (2006β2100), comparing them against a historical baseline (1951β2000). Storm surge estimates were derived from a finite element ocean model configured for the North Atlantic and forced exclusively with EURO-CORDEX downscaled atmospheric fields (atmospheric pressure and winds). Tidal levels were extracted via harmonic analysis of tide gauge records, while projections of relative mean sea level rise were derived from the United Kingdom Climate Projections 18 (UKCP18) dataset. ESLs were calculated using the joint probability method (JPM) by combining storm surges and semidiurnal high tides, with projected relative mean sea level rise added linearly to the estimated ESLs for mid-century (2055) and end-of-century (2100) scenarios. Results indicate that, under future climate projections, the frequency and magnitude of storm surges are expected to remain broadly stable, suggesting that the convolution of high tides and storm surges alone is unlikely to exert a substantial direct influence on ESLs. Instead, projected relative mean sea level rise emerges as the dominant driver for the future ESL increases. High-resolution inundation maps, employing 2 m LiDAR-derived DEMs, were computed for six sites within Sligo Bay to assess the 50-year ESL return level under the RCP 8.5 scenario at 2100. A projected relative mean sea level rise of 0.56 m by 2100 results in a marked increase in inundated area, equating to approximately an increase by 54.2% compared with the historical. These findings underscore that mean sea level rise is the dominant factor in future coastal flood hazards for the northwest of Ireland.