Mafatu is a fifteen-year-old Polynesian boy living on the atoll of Hikueru. After surviving a devastating hurricane as a toddler, he harbors a deep fear of the sea, which isolates him from his courage-prizing culture. Given the nickname "Stout Heart" by his father, he struggles with feelings of inadequacy and shame. Desperate to prove his worth, he sets out on a solitary journey across the open ocean to face his fears.

Tavana Nui is the respected leader of the Polynesian atoll of Hikueru. He values traditional warrior traits and struggles to accept a child who avoids the water. His silent disapproval hangs heavily over his son, serving as the primary motivation for the boy's dangerous quest to prove himself.

Maui is the Polynesian god of fishermen and the controller of ocean winds. He serves as a spiritual protector and guide for those who brave the sea. Believers look to him for supernatural assistance to survive harsh conditions and battle the cruel forces of the deep water.

Moana is the Polynesian god of the sea, representing the unforgiving and dangerous forces of nature. To the islanders, he is a powerful entity commanding the destructive waves and currents. The fearful believe this deity actively seeks to claim those who have previously escaped his grasp.

Mafatu's mother is remembered for her fierce determination to save her child during a violent storm. She used her final physical strength to bring the three-year-old boy ashore before succumbing to the elements. Her death creates the deep-seated trauma regarding the ocean that defines her son's early life.

Uri is a loyal yellow dog and the constant companion of the isolated young protagonist. He stays by his owner's side through periods of social exclusion and joins him in the perilous canoe journey. His presence provides immense comfort and motivation during moments of extreme despair and danger.

Kivi is an albatross rescued and raised by the chief's son. Born with a physical defect that invited mockery from his nestmates, the bird shares an outcast status with his human rescuer. He functions as a natural guide and a symbol of hope, often appearing in the sky to offer direction during critical moments at sea.

Kana is a boy from the village of Hikueru who initially shows kindness to the chief's son. However, peer pressure and cultural expectations eventually lead him to openly mock the fearful boy. His public declaration of cowardice pushes the protagonist past his breaking point, initiating the boy's dangerous ocean journey.