The Danube Delta serves as a natural laboratory for hydrodynamic modeling, owing to its complex morphology and exposure to various natural and human-induced stressors. Additionally, the combination of intense atmospheric conditions, direct morphological modifications within the delta, and freshwater inflows has resulted in a wide array of transport phenomena. As part of the DANUBE4all project, we applied the SHYFEM hydrodynamic model to depict the Danube Delta as a unique river-lagoon-sea continuum. The unstructured numerical grid represents the river branches, the Razelm Sinoie Lagoon System and part of the Western Black Sea. The model's outcomes are used to: 1) analyze the current hydrodynamic conditions and physical connectivity in the different water bodies (river branches, lagoons, coastal zones); and 2) assess the impacts of various river-lagoon-sea reconnection strategies on salinity and the water renewal capacity of the lagoon system.