Invasive mosquitoes present challenges to both public health and ecosystems, demanding a comprehension of their dispersal patterns and genetic makeup. This study integrates genetic analyses of two invasive mosquito species in Belgium, Aedes albopictus and Aedes japonicus, to clarify their introduction pathways and dispersal dynamics. Data were gathered through two mosquito monitoring programs, MEMO and MEMO+, with specimens collected at various points of entry (PoE), including international import companies, highway parking lots, and residential areas. A total of 254 Ae. albopictus and 292 Ae. japonicus specimens were analysed. The northward expansion of Ae. albopictus into Belgium was investigated via active monitoring at PoEs and citizen science initiatives. Thirteen distinct COI haplotypes were identified, with one prevalent haplotype across sampling locations. The disparity in haplotype composition at import companies (indicative of long-distance introductions) versus parking lots/residential areas (suggestive of medium-distance introductions) in Belgium corroborates field observations, where tiger mosquitoes are presumed to hitchhike from established populations in neighbouring countries via passive ground transport. The analysis of seven microsatellite loci within Ae. japonicus populations disclosed genetic disparities between specimens collected at one PoE before and after eradication attempts, hinting at potential new introductions after elimination campaigns. Furthermore, clustering analysis unveiled a genetic correlation between Belgian specimens collected at the border with Germany and populations in western Germany, underscoring the influence of human-mediated transport on invasion pathways. These comparative genetic analyses underscore the significance of vigilant monitoring and targeted control strategies. The genetic investigation of Ae. albopictus and Ae. japonicus enhances our comprehension of their introduction pathways, which is important for effective management and mitigation of invasive species' impacts on public health and ecosystems.