The cOAlition S is an alliance of various national and international research funders who are pursuing the goal of achieving open access for publicly funded research through Plan S. These include, for example, the European Commission (EC), international funders such as the Bill & Melinda Gates Foundation or national research funders such as the Austrian Science Fund (FWF, Austria), the Agence nationale de la recherche (ANR, France), UK Research and Innovation (UKRI, UK) or the Swiss National Science Foundation (SNSF, Switzerland).

Since 2021, open access publications have been mandatory for research projects funded by cOAlition S members. With the Journal Checker Tool, a checking instrument is available that provides information on which OA journals are compatible with the Plan S principles. As a rule, all members of cOAlition S provide financial funding opportunities for Open Access publications. The individual terms can be found in the respective funding guidelines.