No, Switzerland is not eligible for Horizon Europe, as it has not signed the agreement with the European Union to become a third country associated to Horizon Europe. Therefore, legal entities from Switzerland cannot receive EU funding in Horizon Europe projects. However, according to the European Commission, Switzerland should become eligible by the end of 2021.
Researchers in Switzerland can still participate in calls for proposals under the status, albeit to a limited extent, and receive funding directly from the Confederation. However, participation in individual projects, in particular in future calls for proposals from the European Research Council, Marie Skłodowska-Curie Actions and the European Innovation Council, is no longer possible. The Swiss Federal Council’s stated aim remains Switzerland’s full association to Horizon Europe. More information here.
The list of participating Countries in Horizon Europe is available form the European Commission website and has been published on the 17th of June 2021. It lists all other countries eligible for Horizon Europe.