The European Long-Term Ecosystem, critical zone and socio-ecological Research Infrastructure eLTER RI is a distributed pan-European Research Infrastructure of in-situ facilities and central services to support ecosystem research with a holistic approach covering all ecosystem spheres. Its goal is to become formalized as ERIC by 2026–2027, building on decades of national investments in ecosystem research, long-term observations and socio-ecological studies. Today, over 165 research organisations from 28 countries have endorsed its scientific mission, 21 governments have provided formal political support for its establishment and 19 are formally represented in the governing board of the eLTER Interim Council. eLTER RI is designed to generate reliable, long-term knowledge to address pressing societal challenges incl. climate change, biodiversity loss and sustainable resource use. Providing high-quality data and services, it will help Europe remain at the forefront of global ecosystem science. The RI operates as a cost-efficient, distributed network of research sites and services that evolve with emerging scientific needs, supporting evidence-based policymaking and transition towards a sustainable and resilient Europe. EnRich secures final steps of eLTER ESFRI process towards eLTER ERIC. Its mission is to enable frontier science that explains how ecosystems respond and adapt to multiple global change pressures, contributing directly to UN SDGs and European Green Deal. In view of today’s uncertain geopolitical and environmental context, EnRich adopts a phased, flexible approach, supported by advanced system-engineering methods to manage the complexity of specifying-implementing a distributed RI. The approach defines a core Skeleton eLTER RI with essential services that can grow step by step, guided by stakeholder priorities. Through close collaboration with related European projects and infrastructures, EnRich coordinates the distributed development of key cyberinfrastructure, strengthening formal commitments from participating countries and securing long-term sustainability. By bridging ongoing projects with future eLTER ERIC operations, EnRich will ensure a smooth transition, build capacity and expertise and increase user engagement.