This web article summarizes the results of the validation of the first year of S5P OFFL tropospheric ozone column data products (v01.01.05, v01.01.06 and v01.01.07) against co-located vertically integrated ozonesonde profile data collected by the SHADOZ network. All quality indicators remain within mission requirements during the period 30 April 2018 – 25 April 2019. When compared to the ground-based network, QA-screened S5P data have a positive median bias of 14% or 2.7 DU, and the spread in the intercomparisons is 23% or 4.2 DU. Two types of sampling-related bias patterns can be discerned.