Lee Point, at the northern end of Casuarina Coastal Reserve in Darwin, Northern Territory, has historically been a productive breeding area for the northern salt marsh mosquito, Aedes vigilax. The main breeding habitats for this mosquito at Lee Point are coastal interdunal depressions. Sand deposition can form new mosquito breeding sites in the area, with the most recent site to the east of the tip of Lee Point found to be breeding mosquitoes in 2015. Coastal depressions at Lee Point usually breed Ae. vigilax after heavy wet season rainfall, with some sites also breeding after high tides during the wet season. However, the most recently formed interdunal depression was found to breed high numbers of Ae. vigilax larvae following a high tide in the late dry season, indicating the formation of the first dry season Ae. vigilax breeding site at Lee Point. Aedes vigilax is a major pest mosquito and can carry Ross River virus and Barmah Forest virus. This new area of mosquito breeding will be added to the routine larval mosquito control program for Casuarina Coastal Reserve. However, the new site and other interdunal depressions at Lee Point should be investigated for rectification to prevent mosquito breeding.