The biological carbon pump transfers large amounts of carbon from the atmosphere into the ocean’s interior, contributing to oceanic carbon sequestration. Efforts to identify the geographical variability in the transfer efficiency of sinking organic material to depth have yielded inconsistent results. This may in part be due to methodological differences across studies in collecting or analysing particulate organic carbon (POC) flux data. To address this, we compiled data of POC flux and key BCP metrics from selected data-rich locations across biogeographically distinct ocean regions. We integrated multiple BCP observational techniques, encompassing diverse sampling methods, sampling efforts and working protocols, to capture diverse facets of POC flux at varying spatiotemporal resolutions. To make the data comparable across studies, we harmonised reported errors and used Monte Carlo error propagation to calculate uncertainties consistently. Our analysis of BCP metrics from observation-based studies reveals large local uncertainties, blurring expected geographical patterns.