Surrounding the castle, the belt of walls of the Bastioned Fortification of Campo Maior is, today, a testament to the evolution of defensive needs in the border area. Expanded in the reigns of D. João II and D. Manuel I and, subsequently, during the War of the Restoration, for military reasons and due to the population growth, the fortification was recently the target of a recovery process that restored its dignity and the greatness of other times.

The intervention recovered 1600 meters of wall and had the particularity of using traditional techniques and methods.

Visitors can walk through the fortification of Campo Maior and get to know the Half-Bastion of Curral dos Coelhos, the Half-Bastion of Lisboa, the Bastion of S. Sebastião and the Bastion of Boavista.

The bastion of Santa Cruz, which was also recovered, is not available for visit, but can be seen from the aforementioned Half-Bastion of Curral dos Coelhos, as well as the area where the water ditch of the fortification was located, currently occupied by a very careful set of private vegetable gardens.

All along the route, signage is available with information about the fortification, which is an excellent support for visitors who want to know more about this fantastic historic site.