Prometheus's dialogue with Io shows the recurring trend of procrastination. He promises to tell her everything, but when she asks why he has been punished, he postpones his answer by first saying that he has only just finished complaining about it. Prometheus's attempt to tell Io of her future is interrupted by the Chorus, which asks about her past, and Prometheus interrupts the story of her wanderings in the middle and then again near the end. A play requires some interruptions—otherwise we would be listening to boring extended speeches instead of conversations. The constant procrastination of Prometheus's story, however, echoes the general theme of procrastination throughout the play. He shows hesitation several times, deciding whether to speak or to remain silent. Prometheus says nothing to his torturers at first, and hides the secret of his prophesy for some time. The name of Zeus's dangerous future wife cannot be revealed at all until Prometheus is free. The speaking of certain words must sometimes be put off to attain a desired result. The procrastination of Prometheus's revelation of Io's future echoes this theme. When he concludes her story to her, he reveals that Io will be healed and impregnated by Zeus. There is a suggestion that Prometheus's own fate will mirror Io's and that, after a lengthy procrastination, he will also be reconciled with Zeus.

Io's wild thrashing as she is stung by the gadfly contrasts sharply with Prometheus's complete immobility. This is yet another contrast between Io and Prometheus that underscores their underlying similarity. Both are slaves, though one can move and the other cannot. Freedom, then, is not necessarily freedom to move, since Prometheus is freer than Io, because he has the full powers of his mind. Io's example, however, also demonstrates the extent of Zeus's tyrannical power. He can do more than crush by lightning or chain to rocks, he can also turn humans into animals. Io, Atlas, Typho, and Prometheus all provide examples of the metaphorical yoke with which Zeus harnesses his victims.

A good deal of scholarship has been directed toward determining the nature of Prometheus's prophetic power, since often it appears wildly inconsistent. A noteworthy example occurs in this section. Earlier, Prometheus had stated with certainty that a friendship between himself and Zeus will one day be established. Yet here he tells Io with absolute certainty that Zeus will be overthrown by a future offspring. When Io presses him, Prometheus again admits that Zeus can escape this fate if Prometheus is freed. But it becomes clear that, while he predicts the future, Prometheus's knowledge is not certain. The future does not depend only on Fate. Which possibility will come about depends on a decision that Prometheus must make. He must choose whether to tell Zeus of the secret marriage that will destroy him. So far he has categorically insisted at different times that different outcomes will come about, but ultimately it is up to him to choose which one of them will occur—either Zeus will fall, or he will enter into a friendship with Prometheus and be saved. This section shows us the first time that Prometheus confidently prophesies Zeus's downfall. Clearly Io influences his prophecy. Io's presence angers Prometheus, and he prophesies the future that most appeals to him at that moment. Prometheus wants Zeus's downfall, and he says that this downfall will occur. Io's entrance, then, leads to a change in Prometheus's character. Whereas earlier he vacillated between lamenting his fate and looking forward to reconciliation, he now defiantly looks toward Zeus's downfall.

The final ode of the Chorus shows a clear departure from the ode just preceding Io's entrance. Earlier, the Oceanids had spoken of Prometheus's happy marriage to their sister, while now they speak of the danger of marriages between those who are of unequal rank. Earlier, they had shown sympathy for Prometheus, while also expressing their pious devotion to Zeus out of respect for his power. Now, however, the Chorus sympathizes with Io, and their ode says nothing of piety to Zeus. Instead, they express only a fear of Zeus, who endangers others by his anger and his lust. The difference is a subtle one, but clearly the Oceanids have not come away from their encounter with Io unchanged.