Since 2005, guest engagements have taken him among others to the Neue Oper Wien (Seikyo in Tan Dun's opera Tea, Socrates in Krenek's Pallas Athene weint and the title role in the Austrian premiere of Manfred Trojahn's Orest) to the Salzburg Festival (Schreker: Die Gezeichneten), to the Grand Théâtre de Luxembourg (Papageno in The Magic Flute), to the Badisches Staatstheater Karlsruhe (Donner in Das Rheingold), to the Theater an der Wien (G. F. Händel's Giulio Cesare in Egitto, F. Poulenc Dialogues of the Carmelites and Strauss' Intermezzo), to the Operklosterneuburg (title role in Don Giovanni, Escamillo in Carmen and Silvio in Pagliacci) and to the opera houses of Dijon, Caen and Limoges (Papageno in Die Zauberflöte).
In 2018/19, Sander appeared, among other roles, as Papageno in Romeo Castellucci's internationally acclaimed new interpretation of Mozart's Magic Flute at the Opéra de Lille.
He has worked with the conductors Kent Nagano, Bertrand de Billy, Georges Prêtre, Franz Welser-Möst, Leopold Hager, Helmuth Rilling, René Jacobs, Martin Haselböck, Christopher Moulds, Christian Arming, Andrés Oroczco-Estrada, Thomas Dausgaard, Christophe Rousset, Stefan Vladar, Eivind Gullberg Jensen, H. K. Gruber, Andreas Spering and Jérémie Rhorer.
[2] Concert highlights included Gabriel Fauré's Requiem under Georges Prêtre at the Berlin Philharmonie and Schubert's E-major Mass conducted by Franz Welser-Möst.
In addition to his active artistic career, Sander teaches singing at the University of Music and Performing Arts Vienna and is a sought-after lecturer for master classes (among others New England Conservatory of Music in Boston, University of Cartagena Colombia) and a juror at singing competitions (Ada Sari Competition Nowy Sacz / Poland).