Blood-feeding arthropods, particularly mosquitoes, are significant vectors for viruses that pose global health threats. Advances in next-generation sequencing (NGS) and bioinformatics have greatly enhanced our understanding of the diverse viruses these arthropods carry. In French Guiana, the mosquito fauna (Diptera: Culicidae) includes 242 species, nearly half of which belong to the Culex genus. Despite several Culex species being arbovirus vectors, research on them has been limited due to challenges in accurately identifying female specimens in the field. This study employed a metagenomic approach to analyze the virome of field-caught Culex mosquitoes from four different habitats in French Guiana. NGS sequencing identified 57 virus families, revealing viruses that infect bacteria, plants, insects, and mammals, as well as several unclassified viruses. Notably, an uncharacterized phlebovirus from the Bunyaviridae family, related to known pathogenic arboviruses, was discovered. The viral community in these mosquitoes also included many insect-specific viruses (ISVs), which are known to modulate arbovirus transmission and affect mosquito fitness. This preliminary study enriches our understanding of the virome associated with Culex mosquitoes in French Guiana and provides potential insights for developing control measures against arboviruses. The use of metagenomic analysis on arthropod vectors is a promising strategy for monitoring the emergence and circulation of zoonoses and epizootics.