On 31 August 2015, Mastour was loaned to Spain's Málaga CF for two seasons, at the exclusive request of club owner Abdullah al-Thani; as a minor his transfer to another country had to be approved by FIFA, which was not completed until 5 November.
Pada 31 Agustus 2015, Mastour dipinjamkan ke Málaga CF Spanyol selama dua musim, atas permintaan eksklusif pemilik klub Abdullah al-Thani; sebagai minor transfernya ke negara lain harus disetujui oleh FIFA, yang tidak selesai sampai 5 November.