The development and evolution of satellite altimetry and operational oceanography are very closely linked. By providing all weather, global and real time observations of sea level, a key variable to constrain ocean analysis and forecasting systems, satellite altimetry has had a profound impact on the development of operational oceanography. Over the past 20 years, satellite altimetry has been providing a continuous observation of the ocean in near real time. From the launch of Jason-1 in 2001 to the launch of SWOT in 2022, satellite altimetry capabilities have regularly improved from geophysical corrections, processing algorithms including real time processing, altimeter radar technology (SAR mode, swath altimetry) and resolution thanks to the use of multiple altimeters and now swath altimetry. In parallel, major improvements of ocean prediction systems have occurred from the GODAE demonstration in the 2000s up to fully operational systems serving now a large range of applications in the 2020s. The paper provides an overview of the development and evolution of satellite altimetry and operational oceanography over the past 20 years in the context of the Mercator Ocean prediction center, the DUACS system and the EU Copernicus Marine Service. Impact of altimetry on the performances of ocean prediction systems (based on OSEs and OSSEs) is reviewed. The future contribution of swath altimetry on operational altimeter products and ocean prediction is also discussed. Prospects for the next decade are discussed in conclusion.