The mangrove ecosystem is a unique and precious habitat. This ecosystem is scattered along the Red Sea coast. It is considered one of the most distinguished ecosystems worldwidesince it works as an ecosystem stabilizer. It provides the ecosystem with countless benefits, such as shoreline protection, climate enhancement, and nutrient enrichment. Hence, studying the mangrove ecosystem is critically important to understand the habitats around the mangrove, the factors affecting their growth, and the threats they face, in addition to building a baseline of informationto reduce and mitigate them. In the current study, water samples were collected adjacent to the patches of mangroves from different five locations along the Egyptian Red Sea coast (during the summer and winter of 2023). Samples were analyzed for physicochemical characterization, including temperature, TDS, pH, salinity, turbidity, electrical conductivity, and nutrients (NH₄, NO₂, NO₃, PO₄ andSIO₄) for winter-to-summer variation evaluation. Chlorophyll a and b concentrations and total chlorophyll were also assessed. The results showed variations by season and site; the highest temperature was recorded in summer at the Hamata site, reaching 36.20°C. Mostly, the Hamata site showed an increase in nutrient concentrations (NH₄, PO₄, NO₂, NO₃ and SIO₄), reaching 2.42, 2.45, 1.76, 3.75 and 2.94mg/l, respectively. Chlorophyll a and b concentrations, and total chlorophyll in the summer season reached 3.80, 8.23 and 12.03µg/l, respectively.