The increasing use of glass fibre-reinforced polymer composite products across various industries, particularly in wind power installations, is accompanied by significant waste management challenges at their end-of-life. The primary objective is to establish synchronized transnational value chains for the circularity of glass fibre-reinforced polymer composite products. A transnational approach is essential, pooling industry capacities across the region to create an economically viable recycling infrastructure. Actors along the value chain will be mobilized, existing recycling infrastructure will be adapted, and activities within circular loops will be coordinated. Key activities, such as onsite sorting, logistics, storage, and pretreatment of waste to prepare it for recycling and coprocessing in cement kilns will be facilitated, leveraging existing infrastructure for circularity of materials. Furthermore, the recovery of glass fibre and resin through the solvolysis process and reuse of these materials in composite manufacturing will be demonstrated, thereby promoting sustainability and reducing environmental impact across the Baltic Sea region. Sustainability and further expansion of the circular loops will be ensured by delivering a guidebook, which will serve as a practical resource for the wind energy, waste management, cement, chemical, and composite industries in addressing the complex challenges of composite recycling in a collaborative and coordinated manner.