Here we present data which explores how foraminiferal carbonate production changed at an Atlantic, Pacific and Southern Ocean site in response to environmental change during the Palaeocene-Eocene Thermal Maximum (PETM; 56 Ma). We measure the 95th percentile of planktic foraminiferal assemblage test size (µm), size-normalised weight (µg) of Morozovella subbotinae and Subbotina patagonica, coarse fraction percent (%; i.e. the relative contribution of planktic foraminifers to carbonate), and foraminiferal mass accumulation rate (g/cm²/ka) at IODP Site 342-U1409, ODP Site 198-1209, and ODP Site 183-1135.

Foraminiferal mass accumulation rate and age model were calculated as follows: Site 198-1209 follows Westerhold et al. (2018, doi:10.1029/2017PA003306), Site 183-1135 Jiang & Wise Jr. (2009, doi:10.1016/j.marmicro.2009.03.003), and Site 342-U1409 Penman et al. (2016, doi:10.1038/ngeo2757).