Like their previous release, Favourite Worst Nightmare (2007), Humbug was released first in Japan, on 19 August 2009, followed by Australia, Brazil, Ireland and Germany, on 21 August 2009.
Seperti rilis terakhir mereka, Favourite Worst Nightmare (2007), Humbug dirilis pertama di Jepang, pada 19 Agustus 2009, diikuti oleh Australia, Brazil, Irlandia, dan Jerman, pada tanggal 21 Agustus 2009.