Necrotising fasciitis is a rapidly progressing, life-threatening soft tissue infection that carries a high morbidity and mortality, especially in susceptible populations.During the La Niña spring-summer-autumn of 2021-2022, five male patients aged between 59 and 86 were admitted into the Hervey Bay Hospital (Queensland, Australia) intensive care unit (ICU) with necrotising fasciitis and multi-organ failure. All five patients had been in saltwater rivers within the local Fraser Coast area and either hunting for Scylla serrata (commonly known as green mud crabs), or descaling barnacles from their vessels. Following rapid and extensive surgical intervention and aggressive antibiotic and supportive treatment, all five patients were either discharged home or are currently in rehabilitation.With a strong possibility of future floods due to climate change and the cyclic return of the La Niña in the future, this article highlights a potential public health issue. This case series demonstrates the importance of increased vigilance for necrotising fasciitis by frontline healthcare staff after flooding events. Identification and escalation of a potential public health warning about the need for vigilance by people experiencing even the smallest of injury by green mud crabs or barnacles post-flood event may need to be considered.