Concerning global warming, sea level rise is one of the most critical problems. Therefore, it is necessary to find reliable projections for estimating coastal flooding to help manage coastlines more effectively, as the future implications of climate change are uncertain. So, according to the Intergovernmental Panel on Climate Change (IPCC) reports, the rise in sea level poses a significant problem in many coastal areas; hence, studying flooding of low-lying lands along coasts has become a crucial issue and a matter of urgency for countries such as Egypt, which is highly vulnerable to Sea-Level Rise (SLR), raising the temperature and reducing precipitation due to climatic changes. According to IPCC's Fifth Assessment Report (AR5), Sea levels will increase by 2100, 78 cm, and up to 100 cm by the end of this century. However, their magnitude remains indefinite. This study establishes limits on the level of uncertainty in sea-level rise variability. The uncertainty is derived from the analysis of future projections using twenty-eight (28) Global Circulation Models (GCMs) on an annual basis. This study focuses specifically on the coastal zones along the Egyptian Red Sea, from Suez to Hurghada. Based on AR5, four Representative Concentration Pathways (RCP) scenarios were considered until 2100. It was found that there are ranges of possible rises in sea level concerning some models projecting very few centimeters while others go beyond a meter. Using optimal GCM ensembles significantly reduces the uncertainty about predicted values on SLR. Moreover, these results indicate that under each scenario, RCPs 2.6, 4.5, 6, and 8.5, the sea level will increase by 60.5 cm, 71 cm, 77 cm, and 104 cm, respectively.