This study investigated the geomorphological evolution of the Donao coastal alluvial fan between 2009 and 2022 and its associations with typhoon events through field surveys, underwater measurements, image analysis, and numerical modeling. Specifically, the associations of wave-induced erosion of the coastal alluvial fan area with rainfall, landslide area, and tidal correction were explored. The typhoon paths and intensities during Typhoon Goni (2015) were simulated to investigate their effects on wind waves and sediment transport. From 2009 to 2013, the shore-line prograded due to typhoons associated with rainfall-induced landslides. Conversely, the shoreline retreated during typhoons characterized by low rainfall and hourly wind speeds exceeding 135 km/h. These typhoons generally tracked over the offshore waters of northeastern Taiwan and moved toward Japan (Type VI). Therefore, shoreline retreat during a single intense typhoon can outweigh the seasonal effect of the northeast monsoon. Numerical modeling was per-formed to investigate sediment transport trends in the study area during Typhoon Goni (2015). The results revealed the development of strong nearshore currents under both swell and storm conditions, with a dominant east-to-west flow. The simulations indicate that the beach zone (approximately 1 to 3 m in elevation) is highly susceptible to erosion due