Design has a key role to play in developing innovative solutions to current local and global challenges – approaches that must consider the needs of end users and integrate sustainability criteria in processes and strategies for creating products and services. The Circular Design – Learning for Innovative Design for Sustainability (L4IDS) project is a three years Erasmus+ Knowledge Alliance financed project, within the social business and the educational innovation field. The project’s goal is to support the development of skills necessary to promote sustainable production and consumption of products and services in Europe. This is achieved through a knowledge co-creation process and a collaborative action research framework, which led to the development of training materials in order to teach and train students, academics and enterprise staff in Innovative Design for Sustainability (IDfS) strategies. The project is aligned with European Circular Economy policies and contributes to the realization of a more sustainable society. The project has four objectives: (1) to increase and improve the learning strategies of Design for Sustainability; (2) to gather and cluster open educational resources and training courses for industry staff and academics in Innovative Design for Sustainability; (3) to train up innovative and entrepreneurial students designers who are capable of dealing with a transition towards Design for Sustainability as a mainstream design approach, and (4) to establish a basis for a permanent and active European Network of Design for Sustainability. The project was formed by 12 partners who are organised around four country hubs in Ireland, The Netherlands, Catalonia and Sweden. Each country hub consists of one university with education and research in Sustainable Design, one design company with expertise in sustainable design and one national design association. The researchers and professionals involved with the project demonstrate how an interdisciplinary co-design approach tackling wicked design problems can develop viable sustainable and product service systems in partnership with SMEs and students. Following this line of thought, this paper will introduce an internship programme that builds a collaboration among institutions and businesses, while enabling novice designers to experience real-life challenges and developing sustainable design solutions that can transform business practices to address issues of sustainability. Therefore, a total of 11 projects were performed by 48 interns and 16 industry partners. Addressing environmental problems 7 of them were focused on sustainable product solutions and 4 of them offered solutions to enhance the implementation of circular processes in the urban environment. As a reinforcement for the project’s mission, it was recognized as a best practice under the umbrella of the World Environment Day, promoted by the Barcelona City Council.