Marine heatwaves are increasing in frequency and severity and are costing the Australian economy and environment through fisheries closures and biodiversity loss. Recent research has demonstrated that marine heatwaves are having large impacts at depth. The impact of climate change and marine heatwaves on deep reef ecosystems (mesophotic and rariphotic reefs) is limited. The expected impacts of marine heatwaves include sponge bleaching, change in habitat structure, change in community composition, and range extension (and contraction) of species. The Temperate East Network of Marine Parks were designed to protect representative examples of a region’s ecosystems and biodiversity. Through an Our Marine Parks Grant we are combining oceanographic and ecological knowledge to improve our understanding of how climate change is impacting deep reef ecosystems. Working with traditional owners and members of the community we are collecting oceanographic and ecological data across the Solitary Islands, Hunter, and Lord Howe Marine Parks. This data is used to assess the where, when, and how climate change will impact the Temperate East Network of Marine Parks. This information is required to inform park managers of the impacts of climate change on their marine parks and make recommendations that can inform management decision making.