Klang21 regularly tours with the productions of the Pocket Opera Festival Salzburg. Collaborations and guest performances have taken place since 2015 in close cooperation with local institutions and initiatives in Seville, Andalusia, and in the German state of North Rhine-Westphalia.

Long lasting artistic relationships were established with the Ensemble Zahir Sevilla, the Conservatorio Superior de Música «Manuel Castillo» de Sevilla, the Instituto de la Cultura y las Artes de Sevilla – ICAS, the Teatro Central and the Teatro de la Maestranza de Sevilla.

In the German state of North Rhine-Westphalia, cultural policy has focused on contemporary music production since 2015. Here, fruitful collaborations have been established with the Theater and Konzerthaus Solingen, the Hochschule für Musik und Tanz Köln and its practice-oriented location in Wuppertal, the children’s choir of the Musikschule Solingen, the Wuppertaler Bühnen, and the Musik-Theater 21 initiative in Neuss.