Characters
Merliah Summers - A girl from Malibu nicknamed "Queen of the Waves", whose father was a human, but her mother the queen of the mermaids. Her father died when she was a baby so her mother Queen Calissa gave baby Merliah to her grandfather to raise, thinking that she will be safer on land than in the ocean. She is a cool, modern and a little bit sassy girl. She is the main protagonist.
Zuma - A sparkly pink dolphin who shows Merliah around the ocean kingdom and helps her save Calissa.
Fallon - One of Merliah's best friends. She's sassy, outspoken and a little bit sarcastic, but she's a loyal, helpful and great friend. She has dark skin, black hair, and brown eyes.
Hadley - Merliah's other best friend. She's prone to daydream. She is imaginative, funny and silly. Her personality makes her the first one to believe that Merliah is half-mermaid. Hadley has reddish-brown hair, green eyes, and tan skin.
Kayla and Xylie - Best friends and super-stylish mermaids. They own a luxurious boutique under the sea where Merliah gets a mermaid makeover. They own Snouts, a sea lion pup. They help Merliah fight the evil Eris. Kayla has blonde hair with blue streaks, while Xylie has brown hair with purple streaks.
Calissa - Merliah's mother. She was the Queen regnant Queen of Oceana, until her evil younger sister, Eris, stole the throne from her.
Eris - Sister of Calissa and aunt of Merliah. She is the one who overthrew Calissa and became their new evil queen. Everyone in the kingdom is afraid of her. The main antagonist of the film.
Break Summers - Grandfather of Merliah and father-in-law of Calissa. He is the one who raised Merliah and told her about her past.
The Destinies - Three girls named Dee, Deanne and Deandra who own a hair salon and can also see the future. They tell Merliah the three tools she needs to defeat Eris and restore Oceana.
Remo - A yellow-and-green striped sea dragon who is Eris' sidekick. Remo is constantly abused by Eris. He leads Merliah to where Calissa is held as soon as Eris is defeated. He likes to blow through a shell.