Gülsin Onay has given concerts in the major musical centres of the world such as Amsterdam's Concertgebouw, the Berlin Philharmonic Hall, the Vienna Konzerthaus, London's Queen Elizabeth Hall and Wigmore Hall, the Salle Gaveau in Paris, the Washington DC National Gallery of Art and the New York Miller Theater. She has performed as a guest soloist with such leading orchestras as Dresden Staatskapelle, English Chamber Orchestra, Japan Philharmonic, Munich Radio Symphony, Royal Philharmonic, St Petersburg Philharmonic, Tokyo Symphony, Warsaw Philharmonic and Vienna Symphony Orchestras. She has performed under Vladimir Ashkenazy, Erich Bergel, Michael Boder, Andrey Boreyko, Jorg Faerber, Emmanuel Krivine, Ingo Metzmacher, Jose Serebrier, Vassily Sinaisky, Stanislaw Wislocki and Lothar Zagrosek.
Gulsin Onay's international career has spanned over 55 countries across all continents. She has recorded 20 albums that illustrate the breadth of her repertoire as well as her interpretive power. She was honoured with the award of a State Medal by the Polish nation in recognition of her exceptional Chopin interpretations.