A review is given on the geological aspects of carbonate beaches that a geologist thinks may be useful for an engineer. Though, Geologists not involved in engineering problems may find it difficult to know what an engineer should understand about carbonate beaches. Nevertheless, there are at least eleven topics that are potentially very useful for engineers to keep in mind. This paper emits the discussions of certain kinds of carbonate shorelines that are beyond the scope of engineering issues, and focuses on sand-sized coastal carbonate deposits.