Last years have seen a surge of Industrial Symbiosis (IS) development in association with ad-hoc widespread policies to encourage more circular and sustainable practices in the manufacturing sector. Developments in Europe, despite having attracted less attention in the literature, have been significant, driven both by public and private initiative. This paper provides an updated overview of IS activity in Europe, with a mapping of key networks, and a study of prevailing typologies of networks, size, geographical distribution and main streams/ resources traded. The analysis is based on a combination of desk research, gathering of primary data from case studies, a survey to IS network facilitators (n = 22) and in-depth interviews and focus groups (3) with IS practitioners, policy officers and industry representatives (n = 25). The analysis identified pockets of IS activity across all Europe, although varying in nature, resources exchanged and scale and scope of the initiatives. The average size of the mapped networks is approx. 473 members, but the median is approx. 100 members, which indicates high variability of sizes. The geographical scope of the synergies also seems to be dependent upon the following factors: 1) the type of waste stream/by-product; 2) transport costs and 3) market value of secondary materials. Types of waste streams exchanged common to most networks, are chemicals (e.g. chemical base products), biomass and agriculture by-products, wood and wood pellets, plastics, reusable construction materials, equipment, inert waste and water (different qualities including industrial water), residual heat and steam. The paper also discusses key obstacles facing IS development in Europe highlighting: 1) weakness of economic incentives given the low margin of IS projects associated to undeveloped secondary markets; 2) geographical variation of incentives and drivers, given differences in policy frameworks and support mechanisms (e.g. landfill tax levels) and 3) legislative issues that make transport over geographic boundaries extremely complex and administratively burdensome. Finally, the paper concludes with a general discussion of the potential of IS to contribute to the transition to the circular economy (CE) in Europe and identifies some key areas of future research.