O’Neill has participated in various Wagner opera productions at Metropolitan Opera, Covent Garden, London, at the Bayreuth festival, in Paris, Hamburg, Leipzig, the Munich Bavarian Opera and other famous stages.

He debuted at the Sofia Opera in 2024, at Plamen Kartaloff’s premiere production of “Lohengrin”. Critics wrote the following:

“Simon’s bright and elegant timbre corresponds well with the bright character of Lohengrin while at the same time enhancing Simon’s powerful performance. O’Neill was a deeply human Swan Night with brilliant vocals.”

“Simon O’Neille presented a world-class Lohengrin, with his powerful and well-placed tenor technique and with his bright timbre.”

Throughout the following months, Simon will continue his triumphant engagements with a gala concert consisting of fragments from “Tannhäuser” and “Parsifal” with the New Zealand symphony orchestra; he will perform as Tristan in “Tristan und Isolde” at the Sao Paolo theater, Brazil; as Loge in “Das Rheingold” at the Paris national opera.