Barbie 'Brooklyn' Roberts, Barbie 'Malibu' Roberts, and sisters Skipper, Stacie, and Chelsea go on an underwater adventure as they transform into mermaids to help save the world of Pacifica.
| Actor | Role |
|---|---|
 America YoungMalibu (Barbie) (voice) | Malibu (Barbie) (voice) |
 Tatiana VarriaBrooklyn (Barbie) (voice) | Brooklyn (Barbie) (voice) |
 Kirsten DaySkipper (voice) | Skipper (voice) |
 Cassandra Lee MorrisStacie / Mermaid 1 (voice) | Stacie / Mermaid 1 (voice) |
 Natalie LashkariChelsea (voice) | Chelsea (voice) |
 Melanie MinichinoMarlo / Mermaid 2 (voice) | Marlo / Mermaid 2 (voice) |
 Madelyn KratzerAquaryah Aquavilla (voice) | Aquaryah Aquavilla (voice) |
 Tiana CamachoTalleigha Fishtail (voice) | Talleigha Fishtail (voice) |
 Vivian LuIsla / Dr. Tang (voice) | Isla / Dr. Tang (voice) |
 Johnny Yong BoschFinn / Waiter (voice) | Finn / Waiter (voice) |
 Cassidy NaberSareena Seasquid (voice) | Sareena Seasquid (voice) |
 Angela Lee SloanCoralia / Angler Fish (voice) | Coralia / Angler Fish (voice) |
| JJabez ZunigaOslo (voice) | Oslo (voice) |