Aedes japonicus japonicus is endemic in a number of countries in eastern Asia but has been accidently introduced into many regions of the world including Europe. It was first detected in Hungary in 2012. In 2017, robust populations of the species were found at Lake Balaton, one of the most important tourist destinations in Central Europe. Based on the experience gathered in the above localities, habitat requirements, dispersion abilities and human biting behaviour of the species were studied in western Hungary during 2017 and 2018. Our results show that (a) a few years after its detection at the Slovenian-Hungarian border, Ae. j. japonicus is widespread in at least two-thirds of the western half of Hungary; (b) the species spreads quickly in ecological corridors formed by mosaics of rural areas, detached houses, gardens and small forest patches; (c) Ae. j. japonicus occupies artificial containers; (d) expansion of the species into new areas is slowed by extensive closed forest patches.