Sea surface is the time-varying height of the ocean surface relative to a reference ellipsoid. Variations in the sea surface are key indicators of climate change. Monitoring the sea surface is essential for studying ocean dynamics, detecting storm surges, tsunamis, or high wave events, and identifying anomalous water levels, which can indicate unusual water temperature or salinity. Time series of sea level anomalies (deviations of the instantaneous sea surface from the mean sea surface) provided by geodesy are important empirical data to improve numerical weather prediction and climate models. Empirical ocean tide models inferred from geodetic observations are essential for removing tidal signals from satellite altimetry data to analyse mean sea level, as they help to distinguish between ocean tidal variability and long-term sea level rise. These models are also essential for predicting tidal contributions to coastal flooding during storms and for safe harbour navigation and marine operations. Furthermore, empirical ocean tide models are necessary to remove the effects of ocean tides from geodetic observations prior to data analysis as well as for precise orbit determination. The following geodetic products are key to realising, monitoring and applying this Essential Geodetic Variable: