This paper reports on successful seabird mitigation methods implemented in a Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR)-managed fishery. The sub-Antarctic Patagonian toothfish (Dissostichus eleginoides) fishery had a high seabird bycatch mortality rate, particularly of black-browed albatross (Thalassarche melanophris) and white-chinned petrels (Procellaria aequinoctialis) when it began (>5,000 birds per 1,000 hooks). Due to successful mitigation measures and compliance, the fishery has since significantly reduced its seabird bycatch(<0.01 bird per 1,000 hooks). A multitude of measures were implemented, and the following measures are considered to have been important in reducing mortality: restricting the fishery to only operating in the austral winter, using novel marked hooks, 100% observer coverage, restricting longline setting to only occur during nighttime, and requiring weighted hooks so that lines sink rapidly.