The East Sea Real-time Ocean Buoy (ESROB) is a surface mooring that has been in operation off the mid-east coast of Korea since 1999. The ESROB is 9 km off the coast (37° 32.24’N; 129° 12.92’E) in a water depth of 130 m, and provides meteorological and oceanographic (physical and biogeochemical) data every 10 min from Conductivity-Temperature-Depth (CTD) and acoustic Doppler current profiler (ADCP) instruments. The data provided here were collected between 2016 and 2020 and follow the data collected by previous publications. The data were quality controlled and assured using typical data processing methods, and have been used to address temporal variations in currents and water properties, as well as wind-and tide-induced internal waves. The uploaded data files contain variables in a NetCDF format that were obtained during each deployment.