At Epsom on 1 June, Kahyasi started the 11/1 fifth favourite in a field of fourteen for the 209th running of the Epsom Derby. He carried the Aga Khan's chocolate and green second colours, with the first colours being worn by Walter Swinburn on the 2000 Guineas winner Doyoun. Kahyasi broke slowly and was held up by Cochrane in the early stages before making steady progress in the straight. He was switched to the outside to take the lead a furlong from the finish and ran on well to win by one and a half lengths from Glacial Storm, with Doyoun third. At the end of the month, Kahyasi started odds-on favourite for the Irish Derby at the Curragh. He appeared to be struggling at half way and was still well behind entering the straight. Under a strong ride from Cochrane, he caught the long-time leader Insan in the last strides to win by a short head. It was subsequently revealed that he had been struck into by another horse during the race and had won despite sustaining a leg injury.