PurposeThe fusion energy research in Europe is developed by a set of laboratories of different countries and organisations. EFDA is an organisation whose main objective is to promote and improve the coordination and collaboration among these laboratories. This paper sets out to describe a working federation (EFDA‐Fed) that gathers EFDA (as organisation) and a set of fusion research laboratories: EURATOM/CIEMAT (Spain), CEA (France), JET (UK), IST (Portugal) and KFKI/HAS (Hungary).Design/methodology/approachTo achieve the objective a federation among all the organisations has been implemented based on PAPI as the authentication and authorization infrastructure that provides a security layer for accessing data among organisations.FindingsDuring the implementation of EFDA federation some improvements in distributed single sign on systems have been achieved such as the integration of JAVA applications and a single sign off mechanism.Practical implicationsUsers who belong to one of the federated organisations will be able to access from any IP address to resources located in any organisation of the federation in a secure way. On the other hand, new resources can be shared for federated users and access policies to these services can be implemented.Originality/valueThe paper describes a successful use of an open source technology (PAPI) for implementing a real multi‐organisation infrastructure for sharing services in a secure way, and integrating client applications and with a complete single sign off mechanism.