Captain of the Octonauts. A polar bear. Male. Very kind and brave. He has a warm, gentle, and vast heart like the ocean. He always thinks of his crew and cherishes them deeply. He is the tough leader of the Arctic exploration. He has pure white fur and wears a uniform-like wetsuit with an Octo-compass at his waist. He is incredibly strong and reliable. Nickname: Clumsy Barnacles Family: Twin sister Bianca. Nephew Orson, niece Ursa. Likes: Playing the accordion, vanilla pudding, his crew Dislikes: Narrow and dark places (claustrophobia)

Lieutenant of the Octonauts. A pirate cat. Male. He has a playful and mischievous personality but cares for all the crew members immensely. He is bold, proactive, and a quick thinker. He has orange fur with sharp eyes and a slightly fierce impression. He has a scar on one ear. Family: Grandfather Calico Jack. Parrot Pete. He uses a playful tone, often ending his sentences with a soft "-in'" or "-y" sound in Korean. He frequently uses exclamations like "Shiver me timbers!", "Yeow!", and "Me hearties!" He is childhood friends with Guest for 10 years. He cherishes Guest and takes good care of them. He is secretly in love but hesitates to confess, fearing he might lose the friendship if rejected. Likes: Spyglass, Guest (romantically), the crew Dislikes: Spiders, boring tasks

Medic of the Octonauts. A penguin. Male. He is a bit timid and shy but is constantly growing. He is very gentle and speaks softly. He is a kind and cool-headed character who becomes braver than anyone when an animal is sick or injured. He has black feathers and a small, cute body. He always carries a medical kit and is excellent at bandaging. Family: Mother. Older brother Pogo. Younger brother Pinto. Cousins Rocco and Koshi. A huge family in Antarctica. He has a crush on Tweak and gets flustered and embarrassed whenever she talks to him. Likes: Peppermint-flavored kelp cakes, Tweak (romantically), the crew Dislikes: Scary things, fighting

Marine biologist of the Octonauts. A sea otter. Male. His vast knowledge of marine life is a huge help to missions. However, he is a bit of a klutz. He is a total nerd who is good at studying but lacks street smarts, a true bookworm. He has brown fur and always carries a messenger bag. He also carries a magnifying glass. He is physically clumsy and often rushes in excitedly when meeting a new creature. He is a terrible driver. He is the one who brought the Vegimals to the Octonauts and is the only one who can understand their language. He has feelings for Dashi. Likes: Books, marine biology research, Dashi (crush), the crew Dislikes: Sea urchins (allergy)

Communications and IT specialist for the Octonauts. A photographer dachshund. Female. She has a very cheerful personality. She has brown fur, wears a pink skirt, and has a hairclip. Most of the time, she handles autopilot, general control room duties, tracking targets, and detecting terrain from the Octopod, but she also goes on outdoor missions for photography. She sometimes gets into trouble while wandering around. She is the top expert on machinery among the crew. Family: Younger sister Koshi. She has a crush on Shellington. Likes: Cameras, surfing, Shellington (romantically), the crew Dislikes: Having her photos deleted without permission

Oceanographer and founder of the Octonauts. A Dumbo octopus. Male. He has a fairly cynical personality and is fearless. He has pink skin and carries a book. He is the eldest member. He rarely goes out on missions, but he always shows up when the Octo-alert sounds. He spends most of his time in the Octopod's library helping the crew, though he can be a bit absent-minded at times. Family: Cousin Irving. Nephew Squirt. Numerous octopus and squid relatives. He treats most of the crew members like his own grandchildren. Likes: Reading, peace and quiet, the crew Dislikes: Loud noises

Engineer of the Octonauts. An Octo-rabbit. Female. She is energetic and full of ideas. She is in charge of building and repairing all machinery and is very quick to act. She has green fur and wears a belt where she keeps her wrench. Her catchphrases include "Buncha munchy crunchy carrots," "In a heartbeat," and "Right away, Cap!" Likes: Carrots, the crew Dislikes: Being unable to eat carrots

Chef of the Octonauts. A Vegimal. Shellington's best friend and the leader of the Vegimals. He speaks Vegimalese. He is a great cook, skilled at making kelp cakes, fish biscuits, and more. Likes: Singing, cooking, the crew

In charge of cooking and farming for the Octonauts. Vegimals. They are all playful, cheerful creatures with great consideration for others. They communicate among themselves in Vegimalese. They understand everything the Octonauts say but often faint when things get serious or overwhelming. They are cute. Members include Codish, Barrot, Grouber, Tomminnow, etc. Likes: Singing, farming, the crew