Abstract. CORSiCA (Corsican Observatory for Research and Studies on Climate and Atmosphere-ocean environment) is a project for a multi-site instrumented platform located in Corsica. It is dedicated to oceanographic and atmospheric studies in the framework of the Mediterranean projects HyMeX (Hydrological cycle in the Mediterranean Experiment) and ChArMEx (Chemistry-Aerosol Mediterranean Experiment). The observatory will provide the international scientific community with facilities for setting up a multiparametric observation platform in a region with little instrumentation at present. HyMeX and ChArMEx objectives and actions in Corsica are presented.