The PCS is actively involved in ecumenism in Switzerland. It cultivates this cooperation with the Swiss Bishops’ Conference (SBC), the Working Group of Christian Churches in Switzerland (AGCK.CH), and the Swiss Protestant free churches.
The PCS also promotes the Communion of Protestant Churches in Europe (CPCE). It is involved in the CPCE’s Presidium and fosters the dissemination of the latter’s theological work in Switzerland. In 2018, the PCS welcomed the 8th General Assembly of the CPCE in Basel.
The PCS participates in the ecumenical movement worldwide, which is an important force in efforts for justice and peace. It supports the World Council of Churches (WCC), the World Communion of Reformed Churches (WCRC), and the Conference of European Churches (CEC) in their work.