The dataset includes solid-phase geochemistry data of sediment cores from Site C0023 (Hole A) that was recovered during International Ocean Discovery Program (IODP) Expedition 370 in the Nankai Trough offshore Japan in the Pacific Ocean (Drilling vessel Chikyu). Site C0023 was established on 17 September 2016. Coring terminated on 3 November 2016.Algal lipid biomarker analysis was performed after Sturt et al. (2004) and HPLC-MS analyses after Becker et al. (2015). Biomarker concentrations are reported as the integrated peak area of the sum of all detected diols normalized to kg extracted sediment (PA/kg).