Despite his lack of raw vocal power, Coates was still considered to be among the finest of English Wagnerian tenors, especially as Siegfried and Tristan, owing to the strength of his musicianship, his evident intelligence and his impressive deportment on stage. Before the First World War, he also appeared in London as Lohengrin, Tannhäuser as well as Tristan. He sang often in Wagner concerts and appeared as Parsifal in concert performances of the opera. He sang Lohengrin at Cologne, too, and in 1911, performed the Siegfrieds of both "Siegfried" and "Götterdämmerung" for the Denhof Opera Company under Sir Thomas Beecham, appearing opposite the Wotan of Frederic Austin.