This paper presents a hydrodynamic dataset for the Bay of Cádiz in southern Spain, a paradigmatic example of a tidal bay of complex geometry under high anthropogenic pressure. The dataset brings together measured and modeled data on water levels, currents, density, and waves for the period 2012–2015. It allows the characterization of the bay dynamics from intratidal to seasonal scales. Potential applications include the study of ocean–bay interactions, wave propagation, or energy assessments.