Welsh is my mother tongue, and my children speak it. If you come and live in this community you'll work out pretty quickly that it's beneficial to learn the language, because if you're going to the pub or a cafe you need to be a part of the local life.

Terfel took on the role of Wotan for the premiere performances of Robert Lepage's new Met staging of Wagner's Ring 2010-12. His international operatic career began that same year when he sang the Speaker in Mozart's Die Zauberflöte at the Théâtre de la Monnaie in Brussels and he made his United States début as Figaro at the Santa Fe Opera. On 17 July 2010 the cast of this production gave a "concert staging" at the Royal Albert Hall as part of the 2010 BBC Proms which was broadcast on BBC Radio 3 and on BBC Four television.

Terfel was initially associated with the roles of Mozart particularly Figaro and Don Giovanni but has subsequently shifted his attention to heavier roles especially those by Wagner.