This dataset presents foraminiferal stable carbon isotope (δ¹³C) and trace element data from sediment samples of International Ocean Discovery Program Site U1540 (55° 8.47ʹ S, 114° 50.52ʹ W, 3580 m), located in the central South Pacific Ocean. The records cover the timespan between Marine Isotope Stage 11 and 10 (~420-360 ka before present). Foraminiferal δ¹³C was measured on the epibenthic foraminifera Cibicidoides wuellerstorfi and Cibicides kullenbergi and on the planktic foraminifera Globigerina bulloides. The trace element ratios were measured on Cibicides kullenbergi. This dataset provides insights into sub-millennial carbon cycle dynamics in the central South Pacific Ocean during the climatic optimum of Marine Isotope Stage 11 and the following glacial inception.