Given its impact on the climate system, in 2010 soil moisture (SM) was recognized by the Global Climate Observing System (GCOS) secretariat as an Essential Climate Variable (ECV). Since then, the scientific community has been addressing the effects of soil moisture on climate change. In the framework of the European Space Agency (ESA) Climate Change Initiative (CCI) program, a global soil moisture product is being developed by exploiting both passive and active satellite microwave sensors. A first prototype of the global ECV SM product was provided by the University of Technology of Vienna (TUW) in 2012 and provides almost daily SM maps on coarse spatial resolution, which may not be adequate to efficiently describe the dynamics of SM behavior. To evaluate the ECV SM product, we compared it with the finer spatial resolution data retrieved from ENVISAT ASAR WS images acquired between 2007 and 2010 and our in-situ soil moisture measurements at three grassland sites in the south of Ireland. Temporal and spatial variability analysis provided high levels of correlation and low errors between the three datasets, leading to confidence in the new ECV SM global product.