The main objective of the Sentinel-3 mission is to measure sea surface topography, sea and land surface temperature, and ocean and land surface colour with high accuracy and reliability to support ocean forecasting systems, environmental monitoring and climate monitoring.

Among the ocean-related core services expected from Sentinel-3, we can cite numerical ocean prediction, maritime safety and security, coastal zone Monitoring, open ocean and ice monitoring. Sentinel-3 mission's objectives are applied to the ocean, to land surfaces and to cryosphere. For each of these domains, primary variables are : Sea-Surface Height (SSH), Sea-Surface Temperature (SST), Ocean Color (OC), Land Color (LC), Water Surface Level on rivers and lakes and elevation/thickness of floating sea-ice.

The Copernicus Marine Environment Monitoring Service (CMEMS) will distribute Sentinel-3 data for marine operational centers.