The Western Indian Ocean (WIO) region spans across a large latitudinal range, from the Somalia region, influenced by the strong monsoon regime of the northern Indian Ocean, to the southern temperate regime of the tip of South Africa, where the Agulhas current diverges from the northward moving Atlantic Benguela current. It encompasses tropical and subtropical regions of diverse nature, rich stretches of coast along the mainland countries of Somalia, Kenya, Tanzania, Mozambique and South Africa, and vast oceanic areas surrounding the island states of Madagascar, Seychelles, Comoros, Mauritius and French Territories. Geomorphological and oceanographic features define the character of the WIO. The social tissue of the of the WIO, where much of the population lives at the coast, is an amalgam of diverse populations with different origins, a product of the rich and varied political history, where networks of trade interactions have generated a high ethnic and cultural diversity. The cultural heritage is thus important and matches the natural richness of the region. Most countries in the WIO have high population growth rates, and coastal development is expected to grow accordingly. The Regional State of the Coast Report (RSOCR) derives from requirements of the Nairobi Convention and contributes to the United Nations-led production of the World Ocean Assessment (WOA) reports as well as to other global and regional processes, such as the Environment Outlooks coordinated by UNEP. The RSOCR aims to integrate the socio-economic and ecological systems of the WIO region by using a uniform methodology based on the Opportunities Framework and the DPSIR (Drivers, Pressures, Status, Impacts, Responses) approach. The RSOCR’s approach has been adapted from the WOA framework, however the content and organization of the concluding chapters are based on the distinct needs of the WIO region. While the political agenda included the Contracting Parties and their National Focal Points to the Nairobi Convention, the technical process was guided by WIOMSA (Western Indian Ocean Marine Science Association) and involved a representative set of scientists with broad experience in the region. The RSOCR’s main objectives are to i) provide a comprehensive baseline, ii) highlight main opportunities, iii) describe successes and challenges, iv) identify capacity building needs, v) identify knowledge gaps, and vi) propose policy options.