Recent fieldwork in southern Spain and Morocco has revealed strong similarities in the implementation processes and production of building ceramics on both sides of the Mediterranean. They confirm the existence of very strong relations between these two shores, attested by technical transfers and construction materials. By including western Caesarian Mauretania, this study sought to determine whether there was an enlarged Straits Circle that included this bordering region. This hypothesis was based on archaeological and textual evidence of exchanges between southern Spain and western Algeria during the period of the independent kingdoms, which seem to have been dynamic. Pending the renewal of field data, particularly for Caesarian Mauritania, the current results of this investigation, which focuses solely on construction techniques, indicate some similarities but above all some differences. Although Roman techniques were widely adopted in both regions, they show strong local features, in particular through the implementation of the opus africanum, which differ greatly. There is a strong homogeneity in the area of the Strait, whereas Caesarean Mauritania seems to be more oriented towards the eastern African provinces than towards the West.