The Siren is a mythological half-bird, half-woman figure bound to an island. Serving as the poem's speaker, she expresses intense boredom and frustration with her repetitive life. She resents wearing a "bird suit" and squatting on the rocks alongside her companions. To catch her prey, she presents herself as helpless and unhappy, exploiting the savior complex of anyone who hears her.

The Listener represents both the seafaring men of Greek mythology and the literal reader of the poem. They possess a high degree of ego and hubris, believing themselves exceptionally capable of saving the seemingly helpless speaker. Despite seeing the beached skulls of previous victims, they persist in approaching the island under the illusion of their own uniqueness.

The Sisters are the two other sirens who make up the fatal trio on the island. They participate in singing the deadly song that lures men to their deaths. The speaker describes them as unappealing and chaotic, distancing herself from their behavior while remaining permanently bound to them.