World Heritage Sites must necessarily have a demonstrated Outstanding Universal Value and a system and management plan to ensure their protection and conservation. This study focuses on the processes of planning the management of potential serial sites in the World Heritage system. Planning the management of a serial site takes place during the candidacy process, from the initial stages. The World Heritage System provides documents, guidelines, and various tools to define and evaluate the effectiveness of the management of the heritage site. However, according to the literature, the management plans for potential World Heritage Sites, which are submitted with the candidature file, are difficult to implement once the recognition as a World Heritage Site is obtained. There is a discrepancy between submission to the World Heritage List and registration on the World Heritage List. The temporal gap is not merely a matter of time. It is instead something that pertains to the political, administrative, and managerial aspects. These aspects initially promote the creation of the candidacy process but they can, in an unpredictable and rapid manner, evolve and change over time. The aim of this study is to identify a method that can be used to draft an effective management system from the earliest phases of the candidacy process. The study addresses how the antifragile approach can be specialised in its principles to be used as a guide in planning the management of serial sites. Based on the analysis of existing evaluation tools proposed by UNESCO, such as the “Enhancing our Heritage toolkit 2.0”, the principles of the antifragile planning are specialised through the formulation of questions that guide effective planning of management from the first steps of candidacy. The methodology provides a planning guide that integrates the antifragile approach into existing operational tools. This study addresses the question of how to structure a management plan in such a way that it can remain antifragile over time, and how to ensure that it is able to move forward despite discrepancies between the plan’s formulation and its implementation over time. Therefore, it has been developed from direct involvement in the nomination process of a potential serial World Heritage Site which is one of the case studies of an ongoing and broader doctoral project. An antifragile orientation of planning process of management can therefore bridge the gap between the formulation of a plan and its implementation by making it more capable of embracing unpredictable change without succumbing, since an antifragile approach is about recognising the unavoidable unpredictability and uncertainty. Ultimately, the study aims to propose a reflection and a model that can be used to achieve effective management of serial heritage sites to ensure the protection of the Outstanding Universal Value and the controlled development of territorial assets that aspire to achieve the World Heritage status.