The Chapel of Saint Catherine is a small and simple stone construction with a single nave with a rectangular floor plan in which the belfry that rises above the church stands out above all, adorned with two pinnacles and topped with a cross.

The main façade is also adorned with two pinnacles, one on each side. The sacristy, which is also rectangular, appears attached to the rear façade.

The Chapel of Saint Catherine honors the patron saint of the town of Portonovo for whom sailors feel great devotion and to whom they dedicate a festival in the month of November, holding a maritime procession in her honor. The Chapel is also closely linked to the rest of the Portonovo festivals, especially the festivals of the Patron Saint, San Roque.

Formerly the Campo de San Roque was open to the sea and it is said that until the 19th century there was a cannon battery there to defend the entrance to the estuary. Since Portonovo was used as a port of refuge by privateer ships in the 17th and 18th centuries. These defensive cannons are currently buried at the base of the Old Market.