Aedes (Aedimorphus) vexans vexans has become widely distributed in the Australasian and Oceanic Islands zoogeographic regions, and in this paper, we describe the 1st confirmed report of Ae. vexans vexans in Australia. A total of 45 adult individuals were collected around the town of Kununurra in the northeast Kimberley region of Western Australia during the late wet seasons between 1996 and 2003. The majority (84%) was collected at trap sites in or near the Ord Stage I Irrigation Area. Aedes vexans vexans was a minor component of the mosquito population, comprising <0.1% of the total number of adults collected during the study period. The absence of Ae. vexans vexans in earlier collections suggests that it has been recently introduced into northeast Kimberley, most likely by wind currents from the Indonesian archipelago or on occasional light aircraft arriving in Kununurra from nearby islands. The collection of adult Ae. vexans vexans every year since 2001 could indicate that this mosquito has become established in the Kununurra environs, possibly facilitated by the presence of year-round breeding sites created by the irrigation area. Encephalitogenic flaviviruses have been isolated from this species in North America, Europe, and Taiwan, and the vector competence of Ae. vexans vexans for arboviruses prevalent in northern Western Australia, particularly the flaviviruses Murray Valley encephalitis and Kunjin, should be investigated.