Dietary assessment of Late Ceramic Age inhabitants (~AD 1200-1500) from Lavoutte, Saint Lucia, Lesser Antilles was undertaken on human skeletal remains using stable carbon and nitrogen isotope analysis of bone collagen (δ13Cco and δ15N), and bone and enamel bioapatite (δ13Cap and δ13Cen). The isotope data were interpreted in the context of regional food webs, intra-population dietary variation was assessed relative to individual demographic variables and the results were compared to contemporaneous populations at multiple scales. Moderately enriched δ13Cco and elevated δ15N point to substantial contributions from both non-marine and marine protein sources, including nitrogen-enriched pelagic resources. The lack of correlations between δ13Cco and δ13Cap (or δ13Cen) suggests distinct isotopic differences between protein and energy sources. The smaller range and variance of δ13Cco and δ15N values relative to δ13Cap and δ13Cap-co indicate greater inter-individual heterogeneity in dietary energy sources relative to protein sources. Intra-population dietary variation was not, however, correlated with either age or sex, consistent with communal-based food consumption practices. From a broader perspective, the collagen isotope results are comparable with several islands in the Lesser Antilles but are distinct from others, indicating a large degree of regional variation in dietary protein sources, while the bone (and enamel) apatite results are more variable and overlap with many islands in both the Greater and Lesser Antilles indicating wider variation in average (whole) diets. The relative enrichment in δ13Cap and higher δ13Cap-co values are strongly indicative that C4 (e.g., maize) or CAM plants were important dietary components. Overall, the isotopic evidence suggests that the Lavoutte population consumed mixed diets including substantial contributions of both C3 and C4/CAM plant resources, as well as terrestrial and marine protein sources.