István Várdai has been honoured with several prestigious international prizes: in 2014 he won the prestigious ARD Competition in Munich.
In 2009 he was awarded the Junior Prima Prize as the best young artist of the year, and in 2012 he received the prestigious Prix Montblanc awarded to the world's most promising young musician. He won the 63rd Geneva International Cello Competition, along with three special prizes: Audience Prize, “Pierre Fournier” Prize, and “Coup de Coeur Breguet” Prize in 2008, and he took third prize in the Tchaikovsky Music Competition in Moscow in 2007.
In the 2018/19 season, István will perform with Helsinki Philharmonic under Susanna Mälkki, Chamber Orchestra of Europe together with Gidon Kremer and Yuri Bashmet, BBC Philharmonic Orchestra, Manchester Camerata, Orchestre National du Capitole de Toulouse under Klaus Mäkelä, and Hungarian National Philharmonic Orchestra under Hannu Lintu.
Since the beginning of his career, István has played with world-famous musicians and orchestras including: Mikhail Pletnov, Ádám Fischer, Zoltán Kocsis, Howard Griffiths, Gilbert Varga, and St. Petersburg Symphony Orchestra, The Mariinsky Orchestra, Russian National Orchestra and more.