Valentin Jar has performed at many prestigious opera stages including Amsterdam, De Nederlandse Opera, Cologne, Strasbourg, Paris-Bastille, Liège, Avignon, Lausanne, Genève, Toulouse, Caen, Rouen,  De Vlaamse Opera, Ludwigshafen, Lisbon, and at the opera festivals in Wexford and Orange, singing roles such as Triquet in Eugene Onegin, Monostatos in Die Zauberflöte, Mime in Siegfried, Beppe in I Pagliacci, Steuermann in The flying Dutchman, Pedrillo in Die Entführung aus dem Serail, Don Basilio in Le Nozze di Figaro, Valzacchi and Wirt in Der Rosenkavalier, Tanzmeister in Ariadne auf Naxos, Fatty in Rise and Fall of the City of Mahagonny, just to name a few.

Valentin Jar has sung Fürst Ypsheim in Wiener Blut (Krakau/Bydgosz in Poland), Teacher in Lady Macbeth from Mtzensk (De Nederlandse Opera, Amsterdam), Monostatos in Die Zauberflöte  (International Opera Productions, Noord Nederlands Orkest, Idee Fixe, Belgium), Baron Mirko Zeta in Die lustige Witwe (tour through the Netherlands, Supierz Music Management), Erster Bürger and Erster Senator in Die Gezeichneten by Schreker (De Nederlandse Opera, Amsterdam), St.Brioche in Die lustige Witwe (Opera Zuid, Maastricht).

More recently he has performed Spoletta in Tosca and St.Brioche in Die lustige Witwe (both in Alden Biesen, Belgium) Teacher in Lady Macbeth from Mtzensk (Paris, Bastille), and Kromov in Die lustige Witwe (Het Gelders Orkest, Concertgebouw Amsterdam).

Future engagements include Dr. Blind in Die Fledermaus (Noord Nederlands Orkest), Teacher in Lady Macbeth from Mtzensk (Madrid), Wirt in Der Rosenkavalier (De Nederlandse Opera Amsterdam), Altoum in Turandot (Bonn), among others.