There are two types of sea fog along the Shandong Peninsula's southern shore: widespread sea fog and coastal sea fog. Although coastal sea fog predominantly causes considerable interruptions to port operations and coastal activities, existing studies on this phenomenon remain limited and lack depth. This study aims to explore the spatio-temporal distribution patterns of coastal sea fog events over the past 16 years, as well as the underlying formation causes, using data from coastal stations, reanalysis grid data, and satellite observations. The major findings include: 1) Based on the geographical spread of fog areas, we further divide coastal sea fog into five different types. Different high-pressure systems control each type, and their frequency varies significantly from month to month. 2) The spatio-temporal evolution of coastal sea fog displays significant diurnal variation. Rapidly changing weather systems have a substantial influence on the morphology of fog areas, but air-sea temperature and sea surface temperature differences play crucial roles in fog development under slower-changing weather conditions. 3) Most coastal sea fog episodes are accompanied by sea breeze processes. There is an essential temporal correlation between the emergence of sea fog and the establishment of land breeze circulation, both of which demonstrate consistent inter-monthly fluctuations. This study suggests that sea-land breeze circulation may play an important role in the formation of coastal sea fog along the southern shore of the Shandong Peninsula. To better understand this mechanism, additional research should be conducted utilizing high-resolution numerical models.