Star Teens: Mermaids of Aquatopia is an American animated television series made by Man of Action Studios. It is the fourth entry in the Star Teens series.
An underwater kingdom known as Aquatopia is being invaded by a group of water demons and the prince of Aquatopia gathers teenage girls from Hanapepe, Kauai to help save the kingdom by becoming mermaids.
- Makani Pahili - A 15-year old (later 16) Hawaiian girl and the leader of the mermaids with the powers of water.
- Vicki Dames - A 14-year old (later 15) Australian tomboy who loves to surf and the second member of the mermaids with the powers of earth.
- Taylor Holmes - A snobbish 14-year old (later 15) California girl and the third member of the mermaids with the powers of fire.
- Melanie Watanabe - A timid 15-yead old (later 16) Okinawan-Hawaiian girl and the fourth member of the mermaids with the powers of air.
- Prince Noa - The prince of Aquatopia, Noa is one of the few to escape Lady Taunu's raid on Aquatopia. He now must find the ones who must become the Aquatopia Star Teens and train them to use their powers to protect the ocean and get his kingdom back from Lady Taunu. He is also Makani's love interest.
- Pip - A talking dolphin calf who serves as the Star Teens' guide.
- Percy - A sea lion
- Lady Taunu - An evil sea witch
- Leviathan - A terrifying sea monster
- Ernie - The Jamaican owner of a open front restaurant where the Mermaid Star Teens and the teenagers of Hanapepe like to hang out, he is good friends with the Mermaid Star Teens, he is always around to lend a helping hand or advice to various characters, he has a rivialry with Percy the Sealion who always sneaks into his restaurant and eats the food in the kitchen which causes Ernie to chase him out.
- Peter Tahani - He is a laid-back surfer dude with various jobs.
- Aden Strong
- Ashley Johnson - Taylor Holmes
- Auli'i Cravalho - Makani Pahili
- Ava Acres
- Chantal Strand
- Cherami Leigh
- Cheryl Chase
- Cree Summer
- Danny Cooksey
- Daveigh Chase
- Debi Derryberry
- Dee Dee Rescher
- Don Messick - Percy (archive recordings)
- Doug E. Doug
- Greg Cipes
- Greg Eagles - Ernie
- Grey Griffin
- Gwendoline Yeo
- Hynden Walch
- Janyse Jaud
- Jason Marsden
- Jennifer Paz
- Kate Higgins
- Kevin Michael Richardson - Percy
- Khary Payton
- Lacey Chabert
- Lara Jill Miller
- Laura Bailey
- Lauren Tom
- Maia Mitchell - Vicki Dames
- Michelle Ruff
- Olivia Hack
- Pauly Shore - Peter Tahani
- Pinto Colvig - Percy (archive recordings)
- Scott Menville
- Tania Gunadi - Melanie Watanabe
- Tara Strong - Edith
- Tasia Valenza - Lady Taunu
- Terri Hawkes
- Tia Carrere - Makani's mother
- Veronica Taylor - Pip
- Wil Wheaton - Prince Noa