A tsunami can be destructive when it inundates the coastal areas. In recent years, the positive role of coral reefs in mitigating tsunami waves has aroused the attention of scholars. We therefore investigate the tsunami wave interaction with a reef profile via a sophisticated numerical model. We find that the low-lying coastal areas, fringed by coral reefs with milder back-reef beaches and smaller lagoons, are less susceptible to coastal inundation during a tsunami event.