<p>Assessing the ecosystem impact of a species requires information on its foraging ecology across life stages and full distribution. However, such data are often incomplete or entirely lacking for widely distributed species, such as pelagic sharks. We used stomach content and bulk stable isotope analysis in muscle and liver tissue to examine ontogenetic and sex-based variation in the foraging ecology of the salmon shark (<i>Lamna ditropis</i>) in the California Current Ecosystem (CCE), where individuals of all life stages overlap seasonally. Both methods showed that salmon sharks consume teleosts and cephalopods, but trophic niche width and dietary composition varied across sexes and age classes. Juvenile females exhibited the widest niche width among females in both tissues, which narrowed progressively as they matured. Conversely, male niche width decreased from the young-of-year to juvenile stages. Tissue-specific analyses revealed further differences. Liver tissue indicated a diet dominated by continental shelf species, reflective of recent nearshore foraging. Muscle tissue, representing long-term dietary trends, showed planktivorous salmonids and continental shelf species as primary prey for immature individuals, while adult females consumed largely deep-water squid and adult males showed a dietary composition of multiple prey groups, likely due to reliance of oceanic prey during seasonal migrations. These findings highlight the dietary diversity of salmon sharks and underscore the variability in foraging strategies and habitat use across age classes and sexes. Management strategies should consider these differences in foraging ecology, as they may render some specific life stages more vulnerable to environmental changes, anthropogenic impacts, and fluctuations in prey availability.</p>