Mabon, the second of three harvest festivals, occurs on the autumnal equinox (September 22, 2017). The festival name appears to have been coined by Aidan Kelly, a cofounder of the Covenant of the Goddess, who around 1970, named the sabbat after Mabon, the Welsh God. Mabon's story of being kidnapped and brought to the Underworld is the male version of the story of Persephone, whose mother, the earth goddess Demeter, refused to nurture the earth until her daughter was freed from the Underworld.

Mabon marks the first day of autumn. It is a time to feast, rejoice over the grain harvest, and thank the earth for her bounty. With day and night in complete balance, Mabon is also a time for: