The Antarctic toothfish (Dissostichus mawsoni) is a top predator in the Southern Ocean. Understanding its feeding ecology is essential for ecosystem-based management under CCAMLR. We present the first metabarcoding based description of toothfish diet from the Weddell Sea sector (Subarea 48.6) and compare it with long term datasets from the Ross Sea and the Amundsen and Bellingshausen sector (Subareas 88.1 and 88.3). Stomach contents from 124 fish were analyzed using DNA metabarcoding of the COI region with downstream ordination, clustering, SIMPER, PERMANOVA. In Subarea 48.6, diets were dominated by fishes, especially grenadiers (Macrourus spp.) and the icefish Chionobathyscus dewitti, with cephalopods generally less prevalent. Ordinations and clustering revealed a habitat-based split, with slope stations grouping tightly and shelf stations more dispersed, and PERMANOVA confirmed that this structure was significant (R² = 0.436, F = 3.09, p = 0.001). SIMPER indicated that differences between slope and shelf were driven primarily by Macrourus caml and, secondarily, C. dewitti, with shelf signatures distributed across multiple taxa. A constrained ordination further identified depth as the primary gradient shaping prey composition, with fish size and longitude providing additional though smaller effects. Across subareas, median alpha diversity was highest in Subarea 88.3 and lowest in Subarea 48.6, although omnibus tests were not significant. Collectively, these results indicate habitat driven structuring of diet and geographic foraging plasticity in Antarctic toothfish, suggesting the potential for the long-term use of trophic indicators in regional monitoring under CCAMLR.