On 13 June 2013, Bayer Leverkusen confirmed Son's transfer for reportedly €10 million, which was the highest transfer fee in club history at the time.
Op 13 Juni 2013, Bayer Leverkusen Dee Transfert bestätegt fir déi € 10 Milliounen, déi héchst Transfertransfer de Club huet jee an der Geschicht bezuelt.