On the Polynesian island of Motunui, the inhabitants worship the goddess Te Fiti, who breathed life into the ocean many millennia ago, using the pounama stone as her heart and source of her strength.
Maui, a shape-shifting demigod of the wind and sea and master of sailing, steals the heart to give mankind the power of creation. However, Te Fiti disintegrates and Maui is attacked by Te Ka, a volcanic demon. He loses both his magical giant fishhook and his heart in the depths of the sea.
A millennium later, the ocean chooses Moana, the daughter of the Motunui chief Tui, to return Te Fiti’s heart. Tui and Cina, Moana’s mother, try to keep her away from the ocean in order to prepare her to become the chief of the island.
Sixteen years later, a pestilence hits the island, killing the vegetation and reducing the fish catch. Moana suggests going beyond the island’s reef to find more fish and escape the blight, but Tui forbids it. Moana tries to conquer the reef but crashes and returns to Motunui.
Moana’s grandmother, Tala, shows her a secret cave with ships, revealing that their people were travelers until Maui stole Te Fiti’s heart; the ocean was no longer safe without him. Tala explains that Te Ka’s darkness is poisoning the island, but it can be cured if Moana finds Maui and has him restore Te Fiti’s heart. Having received Te Fiti’s heart from the ocean, Tala gives it to Moana. Later, Tala falls ill and, on her deathbed, tells Moana that she should go in search of Maui.
Going to kamakau from a cave, Moana is caught in a typhoon and is shipwrecked on an island, where she finds Maui, who boasts of his accomplishments. She demands that Maui return the heart, but he refuses and locks her in a cave. She escapes and confronts Maui, who reluctantly allows her to sit on the kamakau.
They are attacked by Kakamora, coconut pirates looking for the heart, but Moana and Maui outsmart them. Moana realizes that Maui is no longer a hero since he stole the heart and cursed the world, and convinces him to atone for his guilt by getting the heart back. Maui first needs to retrieve her magic fishhook in Lalotai, the Monster Realm, from Tamatoa, a giant coconut crab.
While Moana distracts Tamatoa, Maui draws his hook but finds himself unable to control his shapeshifting. Tamatoa defeats him, but Moana’s quick wit allows them to escape with the hook. Maui reveals that his first tattoo was obtained when his mortal parents abandoned him as an infant and the gods took pity on him and granted him their powers. After Moana’s reassurance, Maui teaches her the art of sailing, regaining control of her powers, and the two bond.
They arrive at Te Fiti Island, but are attacked by Te Ka. Moana refuses to return, leaving Maui’s hook severely damaged. Not wanting to lose the hook in another confrontation with Te Ka, Maui abandons Moana, who tearfully asks the ocean to find someone else to restore her heart and loses hope.
The ocean obliges and takes the heart, but Tala’s spirit appears, inspiring Moana to find her true calling. She takes the heart and swims back to confront Te Ka. Maui returns with a change of heart and buys Moana time to get to Te Fiti by fighting Te Ka, destroying his hook in the process.
After failing to find Te Fiti, Moana realizes that Te Ka is Te Fiti corrupted without her heart. The ocean clears the way for Moana, allowing her to reclaim Te Fiti’s heart, which heals the ocean and islands of their blight. Maui apologizes to Te Fiti, who repairs his hook and gives Moana a new boat before falling into a deep sleep and turning into a mountain.
Moana says goodbye to Te Fiti as she returns home, where she is reunited with her parents. She takes on the role of leader and guide, leading her people as they resume their journey.
In a post-credits scene, Tamatoa, still on his back, addresses the audience, knowing they will help if he is called Sebastian.