This dataset includes a compilation of new and published size-normalised weight (SNW) planktic foraminifera data, and the associated environmental data which has been extracted from the CMIP6 model ensemble. These data are used in the Bayesian regression modelling as detailed in the manuscript and are split into dataframes used in the species-level modelling and group-level modelling. The dataset includes articles on foraminiferal SNW published until the 31st October 2023 and only includes shell weights that have been normalised to the measurement-based weight (MBW) method (Barker, 2002), using diameter or silhouette area and does not include plankton tow data, samples older than 1000AD, or samples below 4000m water depth. SNW measurements in the new dataset have been collected as per the methodology of Barker (2002). Environmental data corresponds to the location of SNW data collection and the age of the data (i.e. modern or preindustrial). Carbonate ion concentration, salinity and temperature data were derived from Jiang et al. (2023). As environmental data was not available for the Mediterranean, data gaps were filled by extracting data from CESM2 following the same methodology as Jiang et al. (2023). The median of five Earth System Models (CESM2, GFDL-CM4, GFDL-ESM4, MIROC-ES2L and MRI-ESM2-0) were used to extract phosphate concentration and net primary production data.