This dataset contains: Estimates of future and historical daily soil moisture values at 34 locations of the UK COsmic-ray Soil Moisture Observing System (COSMOS-UK) network (three netCDF files starting with "SM"). Each file is for one of the three time periods: 01 December 1980 - 29 November 2000, 01 December 2020 - 29 November 2040 and 01 December 2060 - 29 November 2080. Each file contains data for all 34 locations and 12 UKCP18 ensemble members. Hourly bias-corrected Local (2.2 km) UK Climate Projections 2018 (UKCP18) data (three netCDF files starting with "UKCP18"). Each file is for one of the three time periods: 01 December 1980 - 30 November 2000, 01 December 2020 - 30 November 2040 and 01 December 2060 - 30 November 2080. Each file contains data for all 34 locations, 12 UKCP18 ensemble members and seven variables: specific humidity, precipitation, temperature, downward shortwave radiation, downward longwave radiation, wind speed and atmospheric pressure. Coordinates of the 34 COSMOS-UK locations (csv file). Vegetation information for the considered sites (docx file). The soil moisture estimates are obtained by first optimising pedotransfer function parameters of the JULES land model and driving the model with bias-corrected 2.2 km UKCP18 data. This dataset was generated and analyzed in article: "Future increases in soil moisture drought frequency at UK monitoring sites: merging the JULES land model with observations and convection-permitting UK Climate Projections", by Magdalena Szczykulska, Chris Huntingford, Elizabeth Cooper and Jonathan G. Evans, which is to be submitted to Environmental Research Letters. Details are given in the above-mentioned article and the corresponding supplementary information.