Given the urgent need for multilateral action for planetary health, the scope of planetary health research must be broadened. Key challenges are currently addressed through disconnected approaches and fragmented policy making. Planetary health is an integrative approach that can enhance synergies across multiple fragmented agendas, notably related to health, environment, human rights, and security. It is high time to boost an overlooked area: planetary health diplomacy. This involves measuring progress beyond gross domestic product, broadening the understanding of security to include planetary health, and reforming international organisations to ensure the protection of a rule-based international order. Efforts to address them lack a truly holistic narrative. The science of planetary health goes beyond the currently politicised climate change agenda. So far, planetary health studies have privileged natural science in order to become more impactful. However, the insights gained through this work deserve to be translated into actionable policies for decision makers. More social scientists are therefore needed in this process. Scholars of international relations are under-represented in the planetary health community. The absence of political scientists, lawyers, foreign policy experts, diplomats, and civil servants who are committed to translating planetary health knowledge into effective action comes at a high cost. Policy decisions are being reshaped in the context of evolving pandemic recovery planning, and strategies to advance planetary health that do not take account of unfolding shifts in global power relations are doomed to fail. With only a decade remaining to shift gears towards achieving the SDGs, there is no time to spare.