Athamas was a son of Aeolus (the eponym of the Aeolians) and Enarete in the standard Apollodoran stem. His first wife was Nephele ("Cloud"), who bore Phrixus and Helle. His second wife was Ino, daughter of Cadmus, mother of Learchus and Melicertes. Later tradition gives him a third wife, Themisto, daughter of Hypseus, with further children whose names vary by source.

Through Phrixus he is grandfather of figures connected with Colchis; through Schoeneus (in some branches) he links to the Boeotian parentage of Atalanta.

Nephele left Athamas after he took Ino. Ino's plot against Phrixus and Helle — spoiling the seed-corn and falsifying an oracle — forced Athamas toward sacrificing Phrixus until Nephele's golden ram carried the twins away. Phrixus reached Colchis; Helle drowned in the Hellespont.

Hera's anger at Ino's nursing of Dionysus (or at Athamas's role in related offences) struck the household with madness. Athamas hunted and killed Learchus as a stag; Ino leaped into the sea with Melicertes. Banished, Athamas wandered until an oracle or omen of wolves sharing their prey marked a place of settlement; there he married Themisto. Euripides' lost Ino dramatized Themisto's revenge plot against Ino's children, which backfired when the garments were switched.

Athamas belongs to the Aeolid network that also includes Sisyphus, Salmoneus, and Cretheus; his Boeotian kingship and the Fleece aetiology make him a hinge between Aeolian genealogy and the Argonautica.

The atlas id athamas is the Aeolid Boeotian king. Later geographic names (Athamania) and rare modern uses derive from or echo the mythic figure; they are not separate characters in this entry.