Creusa enters the stage, weeping. Ion asks why she is weeping; Creusa responds that she was transported by a memory when looking at Apollo’s temple but dismisses Ion’s concern, assuring him that it is nothing.

Ion asks about Creusa’s lineage, claiming that he can discern her noble birth from her appearance. Creusa remarks that she is indeed an Athenian, more specifically the daughter of Erechtheus—a legendary king who is said to have slain his daughters in response to an oracle requiring this sacrifice to guarantee victory in a war against the neighboring city of Eleusis. Creusa’s life was spared because she was only an infant. She explains how she was married to Xuthus, an Aeolian distinguished in battle, as a war prize. The two are childless, which is the reason for their visit to the Delphic oracle.

Creusa asks Ion about his own lineage, remarking at how well dressed he is. He explains that he was raised in the temple, knowing only the Pythian priestess as a mother and the god Apollo as at least a notional father. Ion admits that his birth mother was likely a woman attempting to hide her adultery.

Creusa assures him that his birth mother would surely be very proud of him, and she responds that a similar circumstance befell a friend of hers.