More than half of the world's population is lives in coastal areas, and the effects of climate change are increasing. In particular, the prediction, forecasting, prevention and mitigation of disasters in coastal regions underscore the importance of real-time environmental information. This paper addresses the deployment and status of Large Ocean Observation Buoys installed by KIOST in the Yellow Sea/East China Sea in 2021. The buoys provide real-time time-series information not only for ocean physical and meteorological variables, but also for biogeochemical variables. In addition, the installed smart autonomous profiling system enables remote acquisition of vertical profiles of seawater. The data collected by the buoys will be visualized and displayed in real time on a web page. This study demonstrates the role of the buoys in monitoring ocean disasters and hazards using data collected during Typhoon Hinnamnor in 2022 and the low salinity water expansion of the Yangtze River. The use of the buoys for ocean monitoring is expected to be an effective means of responding to dynamic and abrupt environmental changes in the field, thus supporting rapid and effective responses to ocean disasters and hazards.