Coastal-related data are four-dimensional in nature, varying not only in location and water depth but also in time. The heterogeneous and dynamic nature of coastal-related data makes modeling and visualization of these data a challenging task. A new object-oriented spatiotemporal data model to represent dynamic three-dimensional coastal data is proposed in this study. In the proposed model, a set of abstract data types allowing suitable spatiotemporal operations is defined to manipulate complex coastal data. In addition, a logical data model is proposed for the design of a spatiotemporal database. The proposed object-oriented and logical data models are implemented in a real-world coastal information management system in Hong Kong. An elegant visualization framework for displaying the coastal data, based on the concept of a time–depth bar, is presented in the case study.