The study of microfacies, with special emphasis on the significance of larger benthic foraminifera, is used to interpret the occurrence of different marine subenvironments into a mixed carbonate-siliciclastic platform from the upper Campanian in the Prebetic domain, representing the southeastern margin of the Cretaceous Iberian paleoisland. Four foraminiferal assemblages have been recognized, each one specifically assigned to a depositional systems: (1) the outer to middle shelf with Neorotalia? pinetensis, Goupillaudina spp., gavelinellids, Orbitoides tissoti-media, Praesiderolites douvillei, and Navarella joaquini; (2) the upper part of the middle shelf with the presence of seagrass meadows Orbitoides tissoti-media, “Orbitoides” concavatus, Lepidorbitoides campaniensis, Planorbulina cretae, Sirtina ornata, Praesiderolites douvillei, Pseudosiderolites vidali, and Rotalia baetica; (3) the upper photic zone of the inner shelf, with constant wave agitation, inhabited by Orbitoides cf. megaloformis, Lepidorbitoides campaniensis, and Wannierina vilavellensis; and (4) the paralic shallow protected shelf with alternating marine/freshwater influences characterized by charophytes and Suturina minima. Results on larger foraminifera distribution show the similarities and differences with the benthic communities shallow water platform assemblages of the nearby Pyrenean paleobioprovince. This allows to rise the Upper Cretaceous shelfs of the Betic area as a fundamental biogeographic piece for larger benthic foraminifera migration patterns between the Tethyan domain and the other marine domains during the Late Cretaceous.