In this review, the state-of-the-art research advances on coral reef hydrodynamics are introduced from ecology, hazard, geomorphology and engineering perspectives, including reef-top wave-current characteristics and their significance to the reef health, infragravity wave motions around the reef coast and their implications to the coastal flooding mitigation, coral sand movement and consequent reef island evolution, as well as wave interaction with reef-flat engineering structures such as breakwaters and excavation pits. Finally, this review proposes future research directions for the four aforementioned aspects, respectively.