The Super-Kamiokande and T2K Collaborations present a joint measurement of neutrino oscillation parameters from their atmospheric and beam neutrino data. It uses a common interaction model for events overlapping in neutrino energy and correlated detector systematic uncertainties between the two datasets, which are found to be compatible. Using 3244.4 days of atmospheric data and a beam exposure of 19.7(16.3)×10^{20} protons on target in (anti)neutrino mode, the analysis finds a 1.9σ exclusion of CP conservation (defined as J_{CP}=0) and a 1.2σ exclusion of the inverted mass ordering.