The construction of the ships was part of the effort of Portugal to expand its fleet in the face of unrest in the empire and was financed by the United States via the Mutual Defense Assistance Program.

By the 1960s, Portugal retained an extensive empire and the vast majority of the Portuguese Navy's warships were dedicated to patrolling its waters.

Three ships were ordered from Portuguese shipyards to a modified design of the American Dealey-class destroyer escorts.

[a] In the "B" position forward, the frigates mounted two four-barrelled Bofors 375 mm (14.75 in) anti-submarine rocket launchers.

[2][6] Admiral Pereira da Silva-class frigates were equipped with Mark 63 fire-control systems.

This prevented the ships from ever receiving their planned refits and saw maintenance issues increase over their careers.