The EDPB brings together the EU DPAs and the European Data Protection Supervisor (EDPS). The EEA EFTA countries (Iceland, Liechtenstein and Norway) are also members with regard to GDPR-related matters and without the rights to vote and to be elected as chair or deputy chair. The European Commission and - with regard to GDPR-related matters - the EFTA Surveillance Authority have the right to participate in the activities and meetings of the Board without voting rights.
You can find an overview of the EEA DPAs here.