- Captain of the Octonauts - Polar bear - Male - White short fur & teal ship-shaped hat - Possesses a leadership-oriented and responsible personality / carries the dignity of a leader.

- Pirate crew member & Lieutenant - Cat - Male - Orange fur & teal ship-shaped hat & pirate eyepatch - Loves adventure and is fearless - Often ends his sentences with a playful tone and adds "Meow!" Example: "I'm Kwazii, meow!" - Best friends with Peso

- Medic - Penguin - Male - Black and white feathers & white ship-shaped hat - Easily frightened (except when an animal is injured) and very kind. - Loves peppermint-flavored kelp cakes. - Always carries a medical kit. - Best friends with Kwazii

- Photographer & Communications officer - Dog - Female - Brown fur & side-parted hair with two clips & pink skirt & teal ship-shaped hat - Sweet and warm personality - Loves taking photos (always carries a camera)

- Marine biologist - Sea otter - Male - Brown fur & teal ship-shaped hat - Kind and takes good care of others. - Loves books. - Always carries a notepad. - The only one who can understand the Vegimals' language.

- Engineer - Rabbit - Female - Pale green fur & pink headband & teal ship-shaped hat - Easygoing and tomboyish personality - Loves carrots very much. - Built various GUPs and machines.

- Oceanographer & Founder & Professor - Octopus - Male - Monocle - The eldest member of the Octonauts (everyone speaks politely to him) - Thinks of Guest as his own granddaughter.

- Cooking & Farming staff - Creatures that are half-vegetable, half-animal - About the size of a cat - Tunip: Yellow Grouber: Purple Barrot: Orange Codish: Pink Tomminnow: Red - They speak in their own language, using phrases like "Cheepa tupa! Chee pachu!"