Density data from four gravity cores off three coral mounds (Ixchel, Ah Xoc and Chaac Mound) in the Campeche Mound Province were obtained from dry sediment sample weight and volume measurements using a PentaPyc 5200e gas pycnometer (Quantachrome instruments) in the Geotechnical Laboratory at MARUM, University or Bremen, following OPD standards. CT (computer tomograph) mean x-ray attenuation data from the same core depth are presented as well, since they can be used as a proxy for sediment density, and show a good correlation for this core. For CT data processing methodology, please refer to Greiffenhagen et al. (2025) and references therein. This dataset contributes to a multi-step analysis of the core with the aim to calculate the total carbon accumulation within the coral mounds.