Niamh O’Sullivan's recent highlights include role debuts as Octavian (Der Rosenkavalier) for Théâtre des Champs-Élysées and Carmen for English National Opera, her US debut as Offred (The Handmaid’s Tale) for Detroit Opera, Octavian for Garsington Opera, Wellgunde (Das Rheingold) for the Royal Ballet and Opera, Rossweisse (Die Walküre) for Opéra de Monte-Carlo, Wellgunde (Das Rheingold, Gotterdämmerung), Mercédès (Carmen) and Meg Page (Falstaff) for Zurich Opera and Ino (Semele for Théâtre des Champs-Elysées and the RBO. Engagements for 2026/27 include her house and role debuts as Irene (Theodora) for Grand Théâtre de Genève and Lola (Cavalleria Rusticana) for La Monnaie, Brussels, Carmen for Irish National Opera and a role debut for Garsington Opera.