This dataset contains the data plotted in Figure 6 (panels a to d) of the review paper Coccoliths as Recorders of Paleoceanography and Paleoclimate over the Past 66 Million Years by Bolton & Stoll (2025, AREPS; doi:10.1146/annurev-earth-040623-103211). It contains previously published, in some cases updated, data on coccolith on Noelaerhabdaceae coccolith length, thickness, and shape factor (ks) and estimated PIC:POC ratios. The data provide insights into coccolith morphological evolution and degree of calcification, of interest for paleoceanographic and micropaleontological research. Data come from ODP Sites 925 and 926 and IODP Site U1406 sediment cores, drilled in the Atlantic Ocean, and are based on light microscope analyses.