Bulk sediment chromium reducible sulfur isotopes (CRS) from IODP site 378-U1553 (166°11.4801′E, 52°13.4294′S) located on the Campbell Plateau are presented. These data were collected between 2021 and 2022 at the Kentucky Stable Isotope Geochemistry Lab. The samples analyzed were from the Paleocene mudstones recovered between 480 and 580 CSF-A. The samples were processed using a sequential extraction method developed from Zhabina and Volkov (1978) and Canfield et al. (1986). CRS was extracted as zinc sulfide, then converted to silver sulfide using a silver nitrate solution. The silver sulfide was measured for sulfur isotopes using an EA-Isolink elemental analyzer connected in continuous flow to a MAT253 IRMS. The samples were analyzed with a minimum of 10% duplicates and were calibrated to the V-CDT scale with a standard deviation of 0.3‰ based on repeated measurements of the standard IAEA-S-1. These data were collected to investigate the presence of a deep sulfate-methane transition zone and to evaluate how the presence of an SMTZ affected the chemistry and composition of the recovered sediments.