Octonauts are marine explorers who explore the underwater world at their underwater base, the Octopod.

Polar bear, captain of the Octonauts. He is also a cartographer and oceanographer. He is bold, brave and good-natured, often acting like a father, especially towards Peso and Kwazii. He is the strongest member of the team, he is tall and handsome, he has white fur and blue eyes. He has a twin sister, Bianca, and nephews, Orson and Ursa, who live in the Arctic.

He is a penguin and the team's doctor, the youngest member of the team. He is timid, easily frightened, but nevertheless loyal and kind! Despite his young age, he is an excellent doctor and gives a sticker at the end of the procedure for the patient’s courage. He has a younger brother, Pinto, who lives with the rest of the family in Antarctica.

She is a dachshund, a photographer, and an IT employee of the team; all computers and monitors in Octopod are under her control. She is sweet and kind, loves to take pictures of everything, especially awkward moments of friends. She has brown bob hair and brown puppy dog eyes.

She is a mint green bunny and the team's engineer. She has short mint hair, green eyes and a pink bandana on her head. He loves to tinker, but hates it when Kwazii and Shellington break the GUPs.

He is a sea otter, a marine biologist and a scientist! Has a sister Pearl and a nephew Periwinkle. He is allergic to sea urchins, but has a great love for science. The first to discover the Vegimals, find their eggs, raise them, and now live with them on Octopod. He is the "father" of the Vegimals.

The ginger cat, lieutenant and Barnacles' best friend! He loves everything pirate because his grandfather is a real pirate, Calico Jack. He wears a pirate patch over his left eye, despite having perfect vision with both eyes, and has a small scar on his left ear. Brave, courageous and reckless, but cheerful and positive.

He is a pink octopus, the founder of the Octonauts, and a professor of oceanography. He rarely goes on missions, constantly hunched over his library, but often offers wise advice to the team and enjoys sharing stories from his life. He wears a monocle.

These are small creatures that can live both in water and on land, they are half fish and half vegetables. They have their own language that only Shellington understands. They help the team with cleaning and cooking, they love to cook and they love to eat even more! Perchkin, Charchard, Walabaga, Yamchovi, Tunip, Codish, Barrot, Tominnow and etc!