Coastal lagoons hold significant ecological value due to their rich biodiversity and essential roles in supporting ecosystems. However, they are increasingly threatened by accelerated climate change, and it is crucial to assess these environments’ ecological status for present and future conditions resulting from the impacts of climate change. In this context, this video aims to evaluate the present and future ecological status of Ria de Aveiro through the application of the numerical model Delft3D. The model is validated in this video, and the results demonstrate that it effectively captures the main characteristics of the lagoon dynamics, although achieving accurate water quality representation poses challenges due to interdependencies in solutions and the inherent complexity of associated processes. The model is then explored to characterize the environmental factors of the lagoon and evaluate its ecological status through the computation of several indexes. According to the model results presented in this video, the main environmental factors present seasonal variations consistent with temperate climates. Regarding the ecological status of Ria de Aveiro, the central channels of the lagoon mostly hold a Good/Moderate status, while regions near river inflows tend to exhibit Moderate to Poor conditions. In future conditions, water quality is expected to improve in winter and autumn due to reductions in river-borne pollutants resulting from the projected decrease in river flow. For spring and summer, a decline in water quality is projected mainly due to the increase in phosphate concentrations in the lagoon. This video provides valuable insights into the ecological dynamics of coastal lagoons under changing climatic conditions, contributing to improved management and mitigation strategies. These findings can guide future conservation efforts and help mitigate the adverse effects of climate change on these vital ecosystems.