Mitigating plastic pollution requires strong international cooperation because significant volumes of plastic waste are transported across jurisdictions both as waste exports and drifting ocean plastics. Here we estimate which nations are (1) sources for overseas ocean plastics reaching Australian waters and (2) destinations receiving ocean plastics from Australian sources. We then provide actionable recommendations for mitigating plastic pollution in Australian waters and beyond. We estimated that the vast majority of overseas ocean plastics reaching Australia is from Indonesia, and that most of the Australian-sourced ocean plastics reaching overseas territories is entering New Zealand. Key actions for mitigating the ocean plastics issue in Australia include better governance, upgraded enforcement, and increased investments to reduce fossil fuel-based plastic production and to drastically improve both domestic and international waste management infrastructure and operations.