This report presents the latest compilation and quantitative assessment of data on coral reef health by the regional monitoring networks in the WIO, adding to the global GCRMN reports published from 1999 to 2008. The main objective of this report is to provide updated information on the status of coral reefs in the region, up to and including the impact of the 2016 third global coral bleaching event. Secondary objectives are to a) illustrate broad patterns that explain the differing health status of various reefs, and the prospects for reef management in relation to this, and b) present regional drivers of change and how they may evolve in coming years, to help countries in planning for impacts and recovery of coral reefs. It is a joint output of the Global Coral Reef Monitoring Network (GCRMN), the Indian Ocean Commission, Coastal Oceans Research and Development in the Indian Ocean (CORDIO), the United Nations Environment’s Nairobi Convention Coral Reef Task Force and the International Union for the Conservatoin of Nature Species Survival Commission’s (IUCNSSC) Coral Specialist Group.