Egyptian coastal lakes, which represent about 25% of the Mediterranean total wetlands, are considered vulnerable to the impacts of climate change, in particular, the expected sea-level rise (SLR). Manzala Lake is considered as the largest Egyptian coastal lake; it lies on the north-eastern coast of Egypt. Economically, Manzala Lake is considered as one of the most valuable fish sources in Egypt. In this work, the impacts of future climatic changes on the hydrodynamic characteristics of Manzala Lake were investigated. Based on the Fifth Assessment Report (AR5) of IPCC (Intergovernmental Panel on Climate Change, downscaled), Spatially and temporally future projections of meteorological characteristics, such as surface air temperature, precipitation, evaporation… etc. And the mean SLR for two Representative Concentration Pathways (RPCs) scenarios and two different periods in the 21st Century were used as the future projections of climatic changes. These future climate change estimates were used to modify a calibrated hydrodynamic model for the lake to study the future impacts of climate change. The calibrated hydrodynamic model was developed using a two-dimensional, vertically averaged, finite difference hydrodynamic and ecological code, MIKE21. This developed model was calibrated with measured data series for one year (2010-2011). Three hydrodynamic characteristics of the lake were chosen to present the study results, water depths, water temperature and salinity. These features affect the hydrodynamic and ecological status of the lake, which in turn affect all the related activities of the lake. The results show severe impacts of future climatic changes on the studied hydrodynamic characteristics; the maximum average changes will increase up to 189%, 16% and 112% for water depth, water temperature and salinity, respectively, of their basic calibrated values at specific stations and scenarios. A significant spatial distribution for the changes of studied characteristics can be noticed. In the following, the calibrated model is going to be used to simulate the impact of future climatic changes on water quality status of the lake.