Reaching the ambitious United Nations goal of tripling investments in nature-based solutions (NBS) by 2030 will require a multi-faceted understanding of the enablers and barriers to NBS implementation. This deliverable identifies the factors that make NBS distinctly difficult to put into operation as opposed to conventional infrastructure, mainly focused on disaster risk reduction (DRR), and what we can learn from the long experience of ‘grey’ solutions. Infrastructure commonly refers to physical facilities, including but not limited to transportation networks and structures, buildings, water and waste-related networks and facilities, energy networks and plants, and communications networks and facilities. To dive deeper into NBS barriers and enablers, focused largely on DRR, we elicit the views of Norwegian policymakers, as well as NBS contractors, including nature-based enterprises (NBEs), in addressing two barriers: i) lack of knowledge about the effectiveness of NBS and their ability to deliver co-benefits and ii) the lack of qualified contractors who have specialized experience on constructing NBS compounded by a lack of standards, technical guidelines and legal norms. Throughout we document experience of PHUSICOS projects as they have confronted barriers in NBS implementation. We also document selected views of participants of the PHUSICOS Policy Business Forum.