Climate-induced coral bleaching is considered an existential threat to coral reefs globally and is exacerbated by other stressors, including coral diseases. Some corals are more resistant to bleaching than others, for reasons that include genetic variability among colonies, species and locations or gene expression. An evolutionary perspective is therefore integral to understanding resilience in corals. The ability of corals to resist bleaching and disease is additionally dependent on maintaining a healthy microbiome (assemblage of microorganisms, including algae, other protists, bacteria, archaea, fungi, and viruses). While the importance of endosymbiotic microbes in coral health is well known, the effect of temperature on coral-associated bacterial diversity is not fully understood. The many interactions between the coral animal and all its symbionts provide many opportunities for adaptation to changing environments and there is some evidence that corals may adapt to climate change. However, it is recognised that they are unlikely to naturally adapt fast enough to avoid catastrophic loss of species and populations.