Following the Anglo-Dutch sacking of the city in 1596, King Philip II sent the engineer Cristóbal de Rojas to Cádiz to carry out a defense project; Rojas considered that the most immediate intervention was to build a fortification in the bay of Santa Catalina, in order to defend, in this way, one of the most vulnerable fronts of the maritime borders.
The castle is an important example of early modern military architecture and has survived to the present day largely unchanged. It has a star-shaped layout with two distinct fronts: one formed by triangular bastions overlooking the beach, and the other facing the town, where the castle's only gate is located. This gate is protected by two bastions and a channel that regulated the water level through locks. A bridge leads to the single gate, protected by an upper watchtower, beneath which is a commemorative plaque marking the completion of the construction during the reign of Philip II.