Plan S is an initiative launched in 2018 by a group of research funders in Europe, aiming to promote open access to scientific publications. The plan requires that all research outputs funded by participating organizations be freely accessible to the public immediately upon publication, without any paywalls or subscription fees. The goal of Plan S is to enhance the visibility and accessibility of research findings, ensuring that taxpayers and researchers can easily access the results of publicly funded studies. By fostering open access, Plan S seeks to accelerate scientific discovery and innovation while promoting transparency in research.