The unique sea breeze structure in the Beibu Gulf, South China Sea, arises from interactions between complex coastline morphology and background winds. However, relevant research on this phenomenon remains limited. In-depth understanding of these characteristics is crucial for climate prediction and wind energy development. This study analyzed the sea breeze characteristics and influencing factors in the Beibu Gulf using hourly observational data from 15 ground-based meteorological stations in coastal areas of the Beibu Gulf in 2017 and the European Centre for Medium-range Weather Forecasts Reanalysis v5 (ERA5) data.The Weather Research and Forecasting Model (WRF) was used to simulate the high-incidence period of sea breeze (April-June). The coastline is divided into west and east coastal regions based on orientation, and sea breezes are classified into three types: pure sea breeze, clockwise spiral sea breeze, and counterclockwise spiral sea breeze. The differences in the temporal and spatial distribution of different sea breeze types in the two coastal regions were studied, and the three-dimensional structural characteristics of these three types of sea breezes were analyzed. The main findings are as follows: (1) sea breezes in the Beibu Gulf exhibit distinctive spatiotemporal characteristics. Sea breezes occur most frequently from April to June and in September, and least frequently in winter. In spring and summer,sea breezes tend to start earlier and persist longer. Sea breezes weaken with inland penetration. Land-sea temperature difference is a key driving factor for the development of sea breeze, while precipitation suppresses sea breeze formation. (2) Simulation results show that there are obvious differences in the distribution of sea breeze types along different coastlines. Counterclockwise spiral sea breezes dominate in west coast region, constituting 45％ of the total sea breeze days, while clockwise spiral sea breezes dominate in east coast region, constituting 72％. (3) There are also significant differences in the spatial structure of different sea breeze types. Counterclockwise spiral sea breezes develop fastest, cover the largest area, and produce the most intense vertical circulation, significantly interrupting surface temperature rise and elevating coastal humidity. Pure sea breezes rank second, while clockwise spiral sea breezes have the smallest footprint. This study reveals sea breeze characteristics influenced by the Beibu Gulf coastline, providing valuable theoretical support for wind energy resource utilization, meteorological disaster forecasting, and research on air-sea interactions.