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• André de Vanny as Toby Johnson. Toby is a normal teenager and the main protagonist who studies in Sandy Bay High School. He was one of two students involved in an accident following an experiment on a prehistoric rock, which caused him to become a genius. His best friends are Russell Skinner and Dina Demeris. He is also in love with Bianca, a pretty girl in his class.
• Bridget Neval as Elizabeth Hawke. Elizabeth (the main antagonist) was also involved in the accident that turned Toby into a genius. Unlike Toby, she wants to use her newfound genius to take over the school. She dislikes everybody except Toby, whom she is secretly in love with. She is jealous and demonstrates that she will go to any length to get what she wants.
• Benjamin Schmideg as Russell "Russ" Skinner, Toby's best friend. He likes to skateboard and eat pizza. While not being too clever, he is a loyal and brave friend.
• Saskia Burmeister as Dina Demiris. Dina is a good friend to Toby and Russ. She is smart, good looking, boys get on her nerves sometimes and she hates Elizabeth. She goes to Hong Kong in Series 2 and is replaced by Sasha.
• Emma Leonard as Verity McGuire. Verity has been Elizabeth's best friend since Primary School and often assists Elizabeth in her schemes. While she knows Elizabeth goes too far, she does not have the confidence to speak up.
• Brook Sykes as Garth King, the dimwitted school bully. He is often in cahoots with Elizabeth and acts as her spy. He is always up for a fight, especially if it involves Russ.
• Robert van Mackelenberg as Professor Carl Tesslar, the physics professor at Sandy Bay High School.
• Geneviève Picot as Principal Alexa Vyner, Sandy Bay High School's principal.
• Greta Larkins as Sacha Johnson. Sacha is Toby's cousin, who moves to Sandy Bay in Series 2, the last Series of Wicked Science, before it was finished after the last episode.