Mesocosm research provides a transition between controlled laboratory experiments and field studies with facilities found worldwide. Since 2017, AQUACOSM and AQUACOSM-plus projects are leading large-scale, transnational and collaborative mesocosm research across Europe. Recently, early career researchers (ECR) have taken on an informal leadership role within the consortium. This workshop led by the AQUACOSM-plus ECR group is aimed at planning future projects and fostering collaborations. We invite ECRs with interest or experience in mesocosm research to brainstorm ideas and develop proposals for publications. We hope to initiate globally coordinated experiments tackling worldwide environmental issues, and strengthen transnational future collaborations. We will also discuss funding possibilities for mesocosm research on a national or larger scale. The workshop will focus on publication ideas led by ECRs, but we invite researchers from all career stages and fields to join our discussion.