Main

• Boyster Likowski (voiced by Akie Kotabe) is the main protagonist and title character of the series. He is a half-human half-oyster child, has only two hairs and is endowed with superpowers: these include spitting pearls, stretching his limbs to infinity, etc. He is shy and horrified that someone might discover his powers. It is because of an oil spill that he and his brother are mutants, they were found on the beach and then adopted by Lola and Eugene Likowski. He is 11 years old at the beginning of the series but at the end, he is 12 years old. He is a fan of Spido-Dude, a reference to Spider-Man.
• Shelby Likowski (voiced by Matthew Forbes) is Boyster's clam twin brother. He is intelligent and has a very high IQ. He almost never leaves his home and prefers to watch television all day long (which is where he gets all his knowledge from). He is obsessed with the "Prestige and Passion" series and admires the theories of Charles Darwin.
• Rafik (voiced by Rasmus Hardiker) is Boyster's best friend. He's around 11–13 years old, and an overexcited kid. He is one of the only characters in the series to know Boyster's secret. He loves to act, make drama for any situation and often finds things funny even if they aren't really funny. He gets jealous when Boyster spends time with someone else, and he is arrogant and boastful, always thinking he is the best even giving himself the nickname "Rafik the Magnificent".

Supporting

• Eugene Likowski is the adoptive father of Boyster and Shelby. He is a botanist and he is very fond of gardening. He is overprotective of Boyster and wouldn't want anything to happen to him.
• Lola Likowski (voiced by Jules de Jongh) is the adoptive mother of Boyster and Shelby. She is an ingenious person and she loves fixing cars and making objects.
• Alicia (voiced by Lizzie Waterworth) is Boyster's love interest. She is very rich and her parents are stingy and obsessed with money and want her to marry a billionaire at all costs. Alicia dreams of becoming an artist and loves drawing portraits of her beloved cat, Vanilla. Alicia is a nice girl, with a strong sense of integrity, who can't stand being rejected. She likes Boyster a lot but does not suspect that he has a crush on her and, worse, that he has powers. She is around 11–13 years old.
• Ozzy (voiced by Rasmus Hardiker) is a bully at Boyster's school. A vain, idiotic and arrogant person, he loves hitting and putting people down, especially Boyster and Arthur. He seems to be in love with Alicia but obviously she doesn't love him due to his meanness. Ozzy has a lack of self-confidence and would like to be able to impress his two ruthless and muscular sisters by showing them that he can be as strong as them. He is described as being "ugly" by Rafik.
• Arthur (voiced by Rasmus Hardiker) is a socially inept nerd with a passion for the extraterrestrial. He is very smart and is able to create an alien detector, he has been collecting toasters since he was 5 years old and is a fan of Sherlock Holmes. He doesn't have very good breath, he is in the chess club and was in the detective club. He gets harassed and beaten by Ozzy but, despite this, he remains sympathetic towards Ozzy and would like to be his friend. He has a pet spider named Ursula.
• Mr. Marion "Teachinator" Pluss (voiced by Rob Rackstraw) is a teacher at Boyster's school. He is known as the strictest teacher at the school, and is usually seen angry or shouting. He has perceived robotic vision and the students call him the "Teachinator". In the episode of the same name, it is revealed that he only wished to please his late father, who was also a strict teacher.

Season 1