The present study aims to monitor the water quality in Timsah Lake by satellite data, the largest water body in Ismailia district, Egypt. To achieve this, multi-temporal space-born data of both Landsat-8 OLI- (L1 and L2) and Sentinel-2 (2A and 2B) were used during 2014–2020. The methodologies of Case 2 regional coast colour algorithm and aquatic reflectance were applied for monitoring the physical properties of different water characteristics encompassing chlorophyll-a, total suspended matter (TSM), and aquatic reflectance. Satellite data from dry and wet seasons (2014–2020) were selected to examine seasonal and temporal variation. Comparing water quality through the dry and wet seasons (2014–2020) is to avoid the difference in atmospheric conditions and detect seasonal variations. The present study results have shown that the Western Lagoon and its streams are considered the primary source of pollution. Specifically, lower values are observed during August 2015 for TSM (4–17 g m−3) and chlorophyll-a (2–11 g m−3), while the highest values of TSM (23–50 g m−3) appear during August 2018 and for chlorophyll-a during August 2016–2018 (20–40 g m−3). For the wet season for TSM, the lowest values are observed during 2016 (3–10 g m−3), and the maximum is noticed during 2019 (13–29 g m−3); for the chlorophyll-a, maximum values are observed during 2017 (10–23 g m−3).