The dietary patterns of eight adults and one child interred in the Korotuku burial mound (Cikobia, northern Fiji), dated from the late prehistoric/historic period (around AD 1850), have been investigated using carbon and nitrogen stable isotope signatures and dental and oral pathologies. Bone collagen isotopic compositions showed that (1) males and females had similar diets in terms of terrestrial C3 resources and marine fish components and proportions; (2) the proportion of marine fish comprised around 25% of the protein fraction of the diet, and the proportion of vegetal food was high; and (3) one canid that was also studied had a different diet, probably rich in shellfish. Oral and dental examinations of the humans evidenced (1) a low level of dental macrowear, (2) a high rate of carious lesions—interproximal and cervical—of about 15%, and (3) a low amount of abscessing, as well as the presence of alveolar bone recession and calculus in most of the adults. This evidence suggests a diet relying mainly on vegetal food with very limited shellfish consumption. When viewed in the light of ethnohistoric information, this pattern suggests a particular sociocultural behaviour, including food selection, since the analyses of the canid remains indicate that more diversified food resources were available than those consumed by the humans. Overall observations suggest that the deceased in the Korotuku burial mound might be members of an elite living on the island, thus pointing to possible social stratification in the late prehistoric/historic Cikobia community.