This dataset presents the foraminiferal shell fragmentation at International Ocean Discovery Program Site U1540 (55° 8.47ʹ S, 114° 50.52ʹ W, 3580 m water depth) during Marine Isotope Stage 12-10, determined along the sedimentary census counts (Jebasinski et al., 2025). The foraminiferal shell fragmentation was calculated relative to the total number of foraminifera in the sample. A total of 13 replicate counts of the same sample aliquot were completed to determine uncertainties of the census counts.