We present a multi-proxy dataset from a snow petrel stomach-oil deposit, 1401MUM1, from the Theron Mountains (-79.049, -28.329), eastern Weddell Sea region. 1401MUM1 was collected as part of a NERC-funded expedition (2015) from the Theron Mountains, a mountain range in Coats Land. The aim of the analysis is to investigate snow petrel diet during the last 2 ka (late Holocene) and in turn to infer changing sea-ice conditions in the eastern Weddell Sea sector of the Southern Ocean (Penny et al. Antarctic Science, submitted). The data includes results from lipid biomarker analysis (fatty acids, sterols and fatty alcohols), bulk stable isotope compositions (δ¹³C and δ¹⁵N) (Department of Geography, Durham University, Durham, U.K) and non-destructive XRF trace element concentrations (GeoTek Core Scanner, Department of Geography, Durham University, Durham, U.K). The age-depth model is constrained by eight new radiocarbon dates (SUERC - Centre for the Isotope Sciences, University of Glasgow, Glasgow, U.K; University of California-Irvine, California, U.S.A).