Recent research has demonstrated that the Sentinel-1 constellation can be used for continuous tracking of ground deformation phenomena. In this study, the spatial–temporal subsidence characteristics in Nanning were investigated with 18 Sentinel-1A TOPS synthetic aperture radar (SAR) images acquired from 25 June 2015 to 16 December 2016 based on the small baseline subset interferometric SAR (SBAS InSAR) technique. The results showed that the annual average surface deformation rates in Nanning ranged from − 48 mm/year to 20 mm/year, and the maximum deformation was detected in the Langdong area. The SBAS-derived results were validated by Nanning continuously operating reference station (CORS) and levelling measurement data. The correlation coefficient and root-mean-square error (RMSE) between SBAS-derived and levelling-derived mean deformation rates were 0.79 and 2 mm/year, respectively. The maximum discrepancy and the RMSE amounted to 7 mm/year and 4 mm/year comparing the SBAS time-series with the CORS-measured displacement. The verification using levelling and CORS implied high reliability and precision of surface subsidence derived by SBAS InSAR. Our analysis revealed that surface subsidence in Nanning was mainly caused by large-scale urban construction, which should be paid enough attention to avoid further aggravation. With the help of the meteorological data, we also found that the subsidence in Nanning was closely related to climatic anomalies in 2015. This research work will provide important theoretical and practical reference value for urban planning and construction in Nanning.