Green and Blue Infrastructure (GBI) innovations are increasingly promoted in Europe, yet their transfer to new socio-political contexts remains poorly understood. This study applies the Strategic Niche Management (SNM) framework to analyse the conditions under which GBI innovations can be replicated and scaled beyond their original settings. We examine six GBI projects from five EU Member States and assess their perceived transferability through three expert workshops in Belarus, Russia and Ukraine. Using a comparative qualitative design, workshop transcripts were analysed to identify how actors interpret innovation, allocate responsibilities, and negotiate risks within their socio-technical regimes. Across cases, successful transfer depended on leadership by municipal actors, a supportive knowledge base, flexible regulatory arrangements, and targeted communication that strengthens public acceptance. Major constraints included entrenched “business-as-usual’’ routines in administrative and epistemic communities, misconceptions about the costs and maintenance of GBI, weak participatory traditions, and corruption risks. The findings demonstrate that GBI diffusion is highly context-dependent: local actors may be unexpectedly supportive of nature-based solutions, while bottom-up initiatives can serve as viable entry points even within hierarchical governance systems. The study contributes empirical insights from an under-researched region and illustrates how SNM can be operationalised to guide GBI innovation transfer and regime change.