The distributions of dissolved O-2 and CO2 have not previously been systematically compared across the global surface ocean, despite their significance for life and climate. Here we analyze carbon dioxide and oxygen concentrations relative to saturation (equilibrium with the atmosphere) in surface waters, using two large datasets (ship-collected and float-collected data). When applied to a high-quality global ship-collected dataset, CO2 and O-2 concentrations relative to saturation exhibit large seasonal and geographic variations. However, linear fits of CO2 and O-2 deviations from saturation (Delta CO2 against Delta O-2) yield y-intercepts close to zero, which suggests a requirement for data validity. We utilize this finding to investigate the accuracy of carbonate system data from biogeochemical-Argo floats. We find significant discrepancies in Delta CO2-Delta O-2 y-intercepts compared to the global reference, implying overestimations of float-based CO2 release in the Southern Ocean. We conclude that this technique can be applied to data from autonomous platforms for quality assessment. Comparison of carbon dioxide and oxygen concentrations in ocean surface waters relative to saturation can be used to identify erroneous data collected by autonomous ocean platforms, suggests an analysis of data from multiple global datasets