Ariel is the youngest of King Triton's seven daughters, and is 16-years-old. Ariel has a vast fascination with the world of humans, despite contact being forbidden by her father, Triton, who hates humans, but later reformed after he saved by them.
Ariel is a bright, spirited mermaid who is also adventurous and stubborn. Her love for adventure sometimes gets her into trouble. Usually, however, Ariel overcomes any obstacle she faces. Her best friend is a fish named Flounder, and she develops a close relationship with a crab named Sebastian, the court's composer. Ariel is also impulsive, as striking the deal with Ursula and exploring whilst forgetting about the concert. In The Little Mermaid II: Return to the Sea, Ariel matures after becoming a mother. Due to the threat of Morgana, she becomes overprotective of Melody in the same manner she was treated by King Triton in the first film. She is shown to long for the sea, but keeps this hidden from Melody for her own safety.
She is featured in the game not as one the seven Princesses of Heart (her spot is taken by Alice from "Alice in Wonderland") but as one of two female warriors, along with Mulan, to join Sora, Donald and Goofy in the fight against the Heartles, She meets Sora, Donald, and Goofy when she is running away from the Heartless with Sebastian and Flounder. They teach the player how to move around in their new forms, and Sora, Donald, and Goofy cover up the fact that they are from another world by claiming that they are from a distant ocean. When she hears Goofy talking to her father about a Keyhole, she decides to help them find it and manages to find the crystal, that resembles her father's trident, that has the power to reveal the Keyhole. King Triton arrives in time to destroy it, and Ariel leaves in tears.
The sea witch Ursula lures her into helping her steal the Trident from her father, with the promise of helping her get to other worlds, while also revealing that Sora, Donald, and Goofy are in fact from another world. However, things don't go as Ariel planned, as Ursula makes off with the trident and injures Triton. With Sora's help, they defeat Ursula.
After sealing the Keyhole, Sora apologizes to Ariel for lying to her, but she lets it slide, confident that, if they could find a way to travel to different worlds, then so can she.
Ariel made appearence when Chernabog fused the other Disney worlds with hers and also fighting along side with Nick when he searching for few of the Ultimaweapons.