Hydrodynamics and morphodynamics at estuaries and deltas play a major role in global hydrological and biochemical cycles. In tropical regions, they provide invaluable economic and ecosystem services but are very sensitive to changes caused by the development they foster. Tropical estuaries and deltas include integrated land-ocean systems associated with large rivers and productive transition environments, with important quantities of water and sediment discharged to the ocean. The understanding of their circulation and morphodynamic variability, which constitutes a top priority at institutions worldwide, not only provides tools for a rational management of their services such as navigation and tourism. Studying tropical deltas and estuaries also allows the mitigation of inland pollution and sediments delivered to the coastal zone. This session invites studies addressing the hydrodynamics and morphodynamics of tropical deltas and estuaries, with attention to current challenges in an era of expanding population, changing climate, and increasing inland stressors.