Spatial and temporal variations of soil moisture strongly affect flooding, erosion, solute transport and vegetation productivity. Its characterization, offers an avenue to improve our understanding of complex land surface-atmosphere interactions. In this paper, soil moisture dynamics at soil surface (first centimeters) and root-zone (up to 1.5 m depth) are investigated at three spatial scales: local scale (field measurements), 8×8 km<sup>2</sup> (hydrological model) and 25×25 km<sup>2</sup> scale (ERS scatterometer) in a French watershed. This study points out the quality of surface and root-zone soil moisture data for SIM model and ERS scatterometer for a three year period. Surface soil moisture is highly variable because is more influenced by atmospheric conditions (rain, wind and solar radiation), and presents RMSE up to 0.08 m<sup>3</sup> m<sup>−3</sup>. On the other hand, root-zone moisture presents lower variability with small RMSE (between 0.02 and 0.06 m<sup>3</sup> m<sup>−3</sup>). These results will contribute to satellite and model verification of moisture, but also to better application of radar data for data assimilation in future.