This dataset presents benthic foraminiferal (i.e., Cibicides kullenbergi) trace element ratios at International Ocean Discovery Program Site U1540 (55° 8.47ʹ S, 114° 50.52ʹ W; 3,580 m) during Marine Isotope Stage 12-10. Trace element ratios, including Cd/Ca, Mn/Ca, Al/Ca and Fe/Ca, were measured on the benthic foraminifer C. kullenbergi. For most samples the C. kullenbergi Al/Ca ratios were below the limit of detection (LOD), at 0.5 µmol/mol. The samples were reductively cleaned and to determine the 1σ-uncertainty of the analyses, full replicates were conducted. The trace element ratios were measured at the Institute of Geosciences at Kiel University (Kiel, Germany) using an Agilent 7900 inductively coupled plasma-mass spectrometer (ICP-MS). The C. kullenbergi Cd/Ca ratios were converted to Cd seawater (Cd sw) using the calibration and the depth-dependent distribution coefficient (DCd) of 2.9 from Boyle (1992). The Cd sw was used to calculate the [PO₄³⁻]. The [PO₄³⁻] values were additionally combined with a 4 ka smoothed C. kullenbergi and C.wuellerstorfi δ¹³C record to calculate the air-sea equilibration signature (δ¹³Cas) using the calibration from Eide et al. (2017).