The 40th Barbie movie, and the fourth to be a Netflix exclusive.
It follows Barbie 'Brooklyn' Roberts, Barbie 'Malibu' Roberts, and sisters Skipper, Stacie, and Chelsea as they transform into mermaids and go on an underwater adventure to help save the world of Pacifica.
Tropes:
- Alpha Bitch: Talleigha Fishtail serves as one for this movie. She also keeps Sareena Seasquid in tow, although both are redeemed by the end of the movie when they work together with the others to save Pacifica. They also quickly accept Aquaryah as the power keeper, despite previously bullying her for being unable to become one.
- Amazing Technicolor Population: While the majority of the mermaids have normal human skin tones, others, such as Talleigha, Sareena, and Coralia, have Teal, Green, and Blue skin tones, respectively.
- The Call Put Me on Hold: 'Malibu' Barbie, despite almost always being The Ace in previous films, struggles to gain her mermaid powers, failing at every challenge that would activate them for her, while every other character managed to activate theirs with minimal effort. She is eventually able to unlock her Water powers with the assistance of Marlo.
- Cassandra Truth: Nobody took Marlo seriously when she tried to convince them that mermaids actually existed, resulting in them rejecting her research and cutting funding for her projects. 'Brooklyn' Barbie also initially didn't believe that mermaids existed when told by 'Malibu' Barbie.
- Cool Big Bro: Finn tries to be this for his younger sister Aquaryah, and he is very protective of her due to her young age, which she finds annoying.
- Foreshadowing: During the film's climax, Barbie is shown to have excellent communication with the sea creatures, and is even implied to understand them, which the characters are perplexed about because this is something only Water power mermaids can do. When her powers are finally revealed, she reveals herself to be a Water power mermaid.
- Green Aesop: The entire film is intended to be an environmental message against ocean pollution.
- Heel–Face Turn: Upon seeing 'Malibu' Barbie in danger, Marlo decides to cast aside her hatred for Barbie and her obsession with mermaids to help her, which ultimately redeems her in Barbie's eyes.
- Master of All: Aquaryah is ultimately revealed to be the power keeper, the mermaid who has control of all four mermaid powers.
- Personality Powers: Some of the characters' mermaid powers match their personalities, such as 'Brooklyn' Barbie, who has a temper and gains fire powers, and Chelsea, who has a fondness for sea creatures and gains water powers, giving her the ability her to communicate with them.
- The Unreveal: Marlo's deep connection to the ocean is never explained, as she is eventually revealed to be just a normal human like Barbie and her friends.
- World of Technicolor Hair: Mermaids in Pacifica have a diverse range of hair colors, with some characters having multiple colors. As well, when 'Malibu' Barbie and her friends transform into mermaids, their hair also becomes more colorful. However, changes in hair color when becoming a mermaid doesn't appear to be universal, as Marlo's hair remains red even in her mermaid form.
- Young and in Charge: At the end of the film, Aquaryah is revealed to be the power keeper, the mermaid who watches over and controls all four mermaid powers.
- You Don't Look Like You: Isla makes a return in this film, albeit with an inexplicably altered appearance. Her hair is now dark purple rather than the brown with a pink gradient that it was in Dolphin Magic. Her mermaid costume and tail are also no longer pink because they were changed to purple to match her hair, and her skin tone was altered from tanned to being much darker, giving her an Ambiguously Brown appearance. It's possible her appearance was changed due to her looking too similar to Teresa, who would debut as a recurring character in Barbie Dreamhouse Adventures, a series that takes place in the same continuity as this movie.
