Internal waves are a persistent feature throughout global oceans and have significant physical and biological impacts on marine ecosystems, playing key roles through upwelling and mixing in shallow environments. While internal waves are cited as a potential mechanism of thermal refuge for coral reefs, the inherent risk of cold-water stress is poorly understood, particularly as increasing ocean stratification may intensify internal wave activity. Here, we seek to characterise an internal wave propagating in the Central South Pacific that was thought to cause reef-wide bleaching at Ducie Atoll (Pitcairn Islands) in 2016. Anomalously cold water temperature at that time led to the suggestion of the shallowing of the thermocline by an internal wave. Temperature data from the Global Argo Drifter Program are used to analyse isotherm profiles, using isotherm displacement as an indicator of internal wave activity. A generic wave form, fitted to multiple profiles in time and space, provides insight to the mechanisms and characteristics of this internal wave system and can provide insight to the ecological response. The Ducie Atoll is of notable importance due to the remote and pristine nature of the region.