The Biological and Applied Environmental Health Hazards (BAEHH) within the Western Australia (WA) Department of Health (the Department) has a requirement for the provision of helicopter services for the aerial application of mosquito larvicide to manage mosquito-borne disease risks in the South West of WA. The aerial larviciding program is an important preventative public health program. The coastal southwest region of Western Australia experiences annual Ross River virus and Barmah Forest virus activity, which in some years, can lead to significant disease outbreaks in local residents and tourists. By controlling vector mosquito populations, the program aims to reduce cases of both diseases. BAEHH will require mosquito larvicide application (aerial larviciding) to be undertaken in the Peel, Leschenault and Geographe regions in the South West of WA. Mosquito breeding is determined by environmental and climatic factors and as such, the timing of treatment seasons can vary on an annual basis. The services will require the use of a helicopter, specialised application equipment, and suitably qualified personnel to undertake aerial larviciding.