This document reports on the collection of four female Culex quinquefasciatus mosquitoes found in the passenger cabin of a flight from Dar es Salaam, Tanzania to Amsterdam, Netherlands. C. quinquefasciatus is a tropical mosquito species not normally found in Europe. The mosquitoes were identified through morphological and genetic analysis. While aircraft are known to transport mosquitoes globally, successful establishment of new populations is rare, though the risk is increasing with more flights from tropical regions. This represents the first record of C. quinquefasciatus in the Netherlands.