Wind energy installations are increasing rapidly and so is their end-of-life waste. Wind turbine blades consist primarily of glass fibers and are usually landfilled. Given the significant amounts of blade waste expected in the future, circular economy pathways need to be identified for this waste stream. This study investigates the feasibility of the circular economy pathway of mechanical recycling for reuse of end-of-life blades at composite material manufacturing, while optimising the required reverse supply network design in Europe, for 2020 and for 2050. This is achieved through formulating and solving to optimality a Mixed Integer Linear Programming model for the wind blades Supply Chain Network Design problem. The findings indicate a semi-decentralised optimal network design, with 3–4 processing facilities proposed around Europe in all scenarios. The proposed circular economy pathway is economically viable without additional policy support only in 2050; while focusing the efforts only in more favourable areas of end-of-life blade availability can reduce system-wide costs. This study contributes to academic knowledge by formulating and solving for the first time the Supply Chain Network Design problem for end-of-life wind blades and to practice and policy-making by providing insights on the optimal network design, its feasibility and the related implications.