As part of Circular Design: Learning for Innovative Design for Sustainability (L4IDS) Erasmus+ Knowledge Alliance project, a series of internships were conducted in collaboration with local industry partners and interns from four different European countries. The aim of these internships is to develop an adaptable training programme focusing on design for sustainability and circular economy with standardised educational tools and techniques, which can be replicated by other European HEIs. The internship projects were focused on local industry partners’ real-life challenges at the time, and industry partners, interns and researcher/educators facilitating the collaboration throughout the programme. While the immediate feedback upon the completion of the internships was generally positive, as authors we were interested in long-term effects of this experience on industry partners’ professional practices. This paper introduces the internship programme and industry partners’ involvement throughout it and presents the results of interviews with key contacts from each industry partner conducted a year after the internship ended to uncover what/if any changes occurred in practice. The paper presents some considerations on developing the structure of an internship programme on sustainability, ways of collaboration among industry partners, novice designers and universities, observed and potential effects on business practices, and limitations in implementation.