Bella is the new girl in town. She became a mermaid in the sea caves of Ireland when she was ten. Bella is a great singer and provides a musical element to the show.
Cleo has the power to mould water into a different shape, and she later develops the ability to control wind.
She’s quite shy, but a very loyal friend.
Rikki's special power allows her to boil water or anything with water in it. She's not very outgoing, and is quite a rebel, but is always there for her friends.
He's the bad boy in town and Rikki’s love interest. Good looking, spoilt and rich and he'll do everything he can to find out what's really going on with new boy Will.
Will is the new boy in town. The girls find him unconcious on the floor of the mysterious Mako Cave. When he finally wakes up, he reveals that he also has unusual watery talents.
Their loyal and trusted friend (and Cleo's boyfriend). He's always there to pick up the pieces and help the girls avoid trouble and keep their enemies at arms length.