The biodiversity of Red Sea corals captured the attention of some of the earliest European natural historians. Many of the first descriptions of tropical reef corals were based on Red Sea material. Modern approaches to resolve the notorious challenges of coral taxonomy have only recently been applied to Red Sea taxa. This chapter reviews current knowledge of the distributions of coral species in the Arabian region, including assessments of endemism. We also review new species described (or resurrected) since the last major assessment (in 2002). Where sufficient data is available, we highlight within-region distribution patterns. The Red Sea has the highest levels of endemism among all regions of the Indian Ocean. Analysis of the similarity of species composition among the Arabian subregions shows that the Red Sea and Socotra Island are the most speciose, but also have distinct community compositions. The regional diversity of Red Sea corals is likely influenced by the unique environmental gradients of the Arabian region. Despite evolving in testing conditions, Red Sea corals have been impacted by global climate change. Recent thermal bleaching events in the Red Sea highlight the pressures and challenges to future recovery.