["JCMS: Journal of Common Market Studies, EarlyView. ", "\nAbstract\nAfter the COVID‐19 pandemic, the European Union has taken steps towards closer cooperation in health emergency preparedness and response. For this reason, it has established the European Health Union (EHU), which joins an ongoing trend of health securitisation. To specify how the resulting health emergency governance is enacted, this article analyses the EHU's institutionalisation of synchronisation. Synchronisation describes the deliberate temporal ordering of inputs into policy processes. Understanding how synchronisation is enacted in this case is crucial because it allows for a detailed, process‐oriented view of how the actors involved in preparing for and responding to a health emergency shall interact when time is scarce. Therefore, this article asks the following questions: how is synchronisation enacted in the EHU? And how is this reflected in the EHU's institutional set‐up? The article qualitatively analyses the texts of the five legal acts that underlie health emergency preparedness and response. A sophisticated synchronisation architecture emerges, as the practices of synchronisation show multiple adaptations to its institutional setting. The EHU faces the challenging task of achieving synchronised action in the field of EU health security, which is characterised by a broad range of health risks and a multiplicity of actors each responsible for a narrow, specific mandate. This institutional set‐up necessitates synchronisation instruments that allow for flexibility whilst differentiating between the modes of health emergency preparedness and emergency response. By describing these adaptations, this article shows how synchronisation can create the grounds for promising approaches to European policy‐making when it is threatened by crisis situations that create uncertainty and time pressure."]