Investment has always been a challenge in the network industries. Since the 1990s liberalisation has exacerbated this challenge, owing to the different time horizons between the interests of the private sector, the long-term nature of the infrastructure assets and their public service nature. Climate change and the need to decarbonise the infrastructures, as well as the recent focus on digitalisation have only added to the investment challenges in the different network industries. How can we ensure investments in the context of competition, decarbonisation and digitalisation? What should be the role of governments and that of the private sector? How should the right incentives be set? This special issue of the Network Industries Quarterly is dedicated to some of the best papers that were presented at the 10th FSR Annual Conference on the Regulation of Infrastructures “Infrastructure Investment Challenges: reconciling Competition, Decarbonisation and Digitalisation’, which took place on June 10 and 11.