After Sofia helps a little mermaid named Oona, Sofia's amulet grants her the power to transform into a mermaid and visit her new friend's underwater kingdom. But when Cedric (disguised as a seamonster) plots to steal Oona's enchanted Mermaid Comb, danger surfaces for both worlds. With a little help from special guest, Princess Ariel, Sofia embarks on an adventure to rescue Oona and prevent a typhoon before it's too late.
| Actor | Role |
|---|---|
 Ariel WinterPrincess Sofia (voice) | Princess Sofia (voice) |
 Travis WillinghamKing Roland II (voice) | King Roland II (voice) |
 Sara RamirezQueen Miranda (voice) | Queen Miranda (voice) |
 Darcy Rose ByrnesPrincess Amber (voice) | Princess Amber (voice) |
 Zach CallisonPrince James (voice) | Prince James (voice) |
 Kiernan ShipkaPrincess Oona (voice) | Princess Oona (voice) |
 Jodi BensonQueen Emmaline / Ariel (voice) | Queen Emmaline / Ariel (voice) |
 Jess HarnellCedric (voice) | Cedric (voice) |
| SSarah MitchellPrincess Cora (voice) | Princess Cora (voice) |
 Wayne BradyClover (voice) | Clover (voice) |
 Phil MorrisPlank (voice) | Plank (voice) |
 John Ross BowieSven (voice) | Sven (voice) |
 Tim GunnBaileywick (voice) | Baileywick (voice) |
 Jeff BennettFarley (voice) | Farley (voice) |
 Jim CummingsWormwood (voice) | Wormwood (voice) |