Abstract: This data set focuses on ornithogenic soils excavated from a test pit located in an active colony of Pygoscelis spp. penguins on Platter Island in the Danger Islands archipelago along the northeastern side of the Antarctic Peninsula in December 2015. It contains radiocarbon dates of recovered penguin tissues and the estimated age of ornithogenic soils by depth. It also contains measurements of carbon (δ13C) and nitrogen (δ15N) stable isotope values of Pygoscelis spp. penguins eggshell membrane and feather samples and Antarctic fur seal (Arctocephalus gazella) hair sample recovered from these ornithogenic soils. Accelerator Mass Spectrometry (AMS) was used to obtain radiocarbon dates at the Woods Hole National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) facility. Radiocarbon Dates were corrected for the marine carbon reservoir effect and calibrated to calendar years before present (cal years BP) using a ΔR of 750 ± 50 years and the MARINE13 calibration curve in Calib 7.04. The rbacon package ver. 2.3.9.1 in R was used to estimate age at depth of each soil level expressed as years relative to the common era (CE). Stable isotope analyses were conducted using an elemental analyzer coupled to a continuous flow stable isotope ratio mass spectrometer at Louisiana State University. The data set also includes associated data such as excavation date, location, site names, latitude/longitude, species, date of excavation, tissue used for radiocarbon dating, and carbon to nitrogen ratios. Details of the data set and all relevant methods are provided in Kalvakaalva et. al., 2020.