With 115 organisations across 21 European countries, The Distributed System of Scientific Collections (DiSSCo) represents today the largest ever formal agreement between organisations of this type, in the world. These organisations have joined forces to develop and operate as a distributed pan-European Research Infrastructure. The DiSSCo RI works for the digital unification of all European natural science assets under common curation and access policies and practices that aim to make the data easily Findable, more Accessible, Interoperable and Reusable (FAIR). DiSSCo will deploy a comprehensive portfolio of services across three main categories: a) e-Science Services, b) Physical and Remote Access Services and c) Support and Training Services. DiSSCo Prepare acts as the main vehicle through which DiSSCo RI will raise its overall maturity and set itself in a position to implement its construction programme. DiSSCo Prepare aims at 1) improving the overall Implementation Readiness Level (IRL), and 2) delivering the DiSSCo Construction Masterplan. The DiSSCo IRL is defined as the measure of the ability to embark on specific implementation actions (construction projects) based on clear, actionable guidelines with minimum risk, and across the scientific, data, financial, technological and organisational dimensions of the infrastructure. DiSSCo Prepare will raise the readiness level of the RI across all five dimensions. The DiSSCo Construction Masterplan will be considered as the final output of the project and will effectively be used as the organisational, financial and technical guiding framework for the construction of the infrastructure (including establishing the legal entity).