Western Australia supports an array of shallow water marine ecosystems along its vast coastline. This includes a diverse range of tropical and sub-tropical benthic habitats such as coral reefs, seagrass meadows and sponge gardens. . However, since winter 2024, elevated seawater temperatures have persisted off the north-west coast, resulting in an unprecedented marine heatwave event over the summer/autumn period. Sea surface temperatures off the Kimberley, Pilbara and northern Gascoyne remained 1-4°C above long-term average from December 2024 until April 2025 and are predicted to remain well above average into the winter months. This has resulted in observations of significant coral bleaching from southern Ningaloo (24 degrees latitude) to the northern Kimberley and offshore atolls (13 degrees latitude). Here we present a summary of aerial and in-water coral bleaching surveys conducted across the broader region from February to May 2025. Record levels of bleaching were observed across almost all regions surveyed, with signs of coral mortality becoming evident in some locations by mid-April. While smaller-scale bleaching events have occurred in Western Australia in the past (notably 2011, 2013, 2016 and 2021/2022), this is the first time that a single event has been recorded over such a large latitudinal gradient. The current event is considered unprecedented for Western Australia and represents one of the most severe bleaching events on record for Australia. Impacts to associated communities are yet to be fully understood, with ongoing monitoring and research needed to assess the long-term ecological consequences.