The Preparatory Phase (PP) of the ELI project started in November 2008 and finished in December 2010. It was funded within Framework Programme 7 with about 6 Million Euros. Decision had been made about the distributed research infrastructure, based in three different sites (Czech Republic, Hungary and Romania), postponing the decision on a possible fourth site (Ultra-High-Field Science) to a later time. Result of the Preparatory Phase is the ELI White Book.

ELI is the first ESFRI project to be implemented in the „new” EU Member States that joined after 2004. The Implementation Phase of the first three pillars, proceeding in parallel in Dolní Brezany (Czech Republic), Szeged (Hungary) and Magurele (Romania) started in 2011. It is being funded by a combination of European Regional Development Funds (ERDF) and national co-financing contributions from the host countries, totaling about 850 Million Euros. The ELI Delivery Consortium International Association (AISBL) was established in August 2013 comprising of representatives from the three host countries and other EU Member States, namely France, Germany, Italy and the United Kingdom in order to coordinate the parallel implementation and prepare for the joint operation phase.

Operation Phase is expected to commence in 2019, reaching full operation from partial operation after a ramp-up period. The three pillars will be operated, governed and funded by a newly established European Research Infrastructure Consortium ERIC, composed of interested member countries. ELI will operate as an international laser user facility, open to access by an international user community. As an ERIC the three Research Infrastructrures will be able to set their own procurement rules, lower their operation costs and harmonize their access policy.