Coral reefs are increasingly undergoing rapid changes, with marine heatwaves emerging as the primary global threat. During the fourth global coral bleaching event (GCBE4), Western Australia experienced its most severe mass bleaching on record. Thermal stress reached 20–30 Degree Heating Weeks (DHW; NOAA Coral Reef Watch) across multiple reef systems, resulting in widespread bleaching and mortality. This event spanned >1,500 km of coastline, from southern Ningaloo (24°S) to the northern Kimberley and offshore atolls (13°S), marking the first time a single bleaching event has affected such an extensive spatial scale in WA. We assessed post-bleaching coral cover and taxonomic composition using diver-based and remotely operated vehicle (ROV) photo-transect surveys across several reef systems including multiple marine parks integrating data from several monitoring programs to capture responses across remote reef systems. Preliminary results indicate coral cover has been reduced by 50-95% in multiple reef locations as a direct result of the heatwave event, with site-specific shifts toward stress-tolerant taxa such as Echinopora, Cyphastrea, Turbinaria and massive Porites. These changes have implications for habitat complexity and reef-associated biodiversity. Our findings highlight the role of multiple sequential heatwaves in shaping community trajectories and recovery potential. Understanding these dynamics is critical for adaptive marine park management, including informing marine park zoning and early-stage restoration priorities.