Here, we provide diagnostic plots for the 2021 assessment model for Kerguelen Island EEZ Patagonian toothfish (Dissostichus eleginoides) presented in Massiot-Granier et al. (2021a), following the recommendations of WG-SAM-2015 (SC-CAMLR-XXXIV 2015 Annex 5). The stock assessment model is described in Massiot-Granier et al. (2021a), and a detailed description of the stock area, stock assessment methods and the stock assessment parameters are given in MassiotGranier et al. (2021b).