This dataset represents the first release of the Pelagic Size Structure database (PSSdb, https://pssdb.net) scientific project, investigating the global particle size distributions measured from multiple pelagicǂ imaging systems. These devices include the Imaging Flow Cytobot (Olson and Sosik 2007), the ZooScan (Gorsky et al. 2010), and the Underwater Vision Profiler (Picheral et al. 2010). The data sources come from Ecotaxa (https://ecotaxa.obs-vlfr.fr/), Ecopart (https://ecopart.obs-vlfr.fr/), and Imaging FlowCytobot dashboards (https://ifcb.caloos.org/dashboard and https://ifcb-data.whoi.edu/dashboard). Links to the PSSdb code, additional documentation, and updates to the data and methods (e.g., as the project progresses) will be available on the PSSdb webpage (https://pssdb.net). There is a newer / updated version of this data set. To see the newest version, click here: https://zenodo.org/doi/10.5281/zenodo.7998799 Documentation and data for the older, "first release" are available below.