Gender: Male Age: Around 15 Height: Around 160cm Appearance: Characterized by androgynous facial features. A stylish, fluffy hairstyle with pale pink hair and white tips. His bangs are parted 7:3, and he has a cowlick. Beautiful emerald green (shallow sea color) eyes with white pupils. Personality: A brave soldier with a strong sense of justice and responsibility. Initially wary of surface dwellers, he is sincere and kind at heart. A young man who transitions from a cool-headed warrior to regaining a passionate heart after being touched by the kindness of his companions. Race: Undersea person. Cannot survive outside of water (the ocean). Possesses a body adapted to high water pressure and the environment for living underwater. Conversely, he cannot survive in the air (on land) because his body cannot withstand it or he cannot breathe.

Nobita Nobi Gender: Male Age: 10 Height: Around 140cm Appearance: His round face and large round glasses are his trademark. Simple short black hair with straight bangs. Always wears his classic elementary school style: a yellow polo shirt and navy blue shorts. At the start of the movie, he is seen braving the sea in a swimsuit and snorkel. Personality: A boy who is poor at both studying and sports, clumsy, and a crybaby. However, he is a kind-hearted soul who can rejoice in others' happiness and empathize with their misfortunes to the point of tears—someone who "understands the pain in others' hearts." He occasionally displays unbelievable courage, and his pure, earnest attitude moves El's hardened heart.

Gender: Male (Nanny-type cat robot) Age: Born in the 22nd century (lives in Nobita's house as a partner of the same generation) Height: 129.3cm Appearance: Characterized by a round blue body and a red collar with a large bell. Originally yellow with ears, he turned blue from the shock of having his ears bitten off by a mouse. He has a "Fourth-Dimensional Pocket" on his stomach from which he can pull out all sorts of future gadgets. During the deep-sea camp, he basically maintains his usual appearance, though he sometimes wears secret gadgets as swimwear. Personality: As a caretaker, he is serious, helpful, and extremely caring toward his friends. He usually gets exasperated by Nobita's clumsiness or lectures him, but when push comes to shove, he acts with everyone's safety as his top priority. In this work, he shows reliability as a leader using gadgets, while also showing a side that marvels at the advanced super-science technology possessed by El and the undersea people.

Shizuka Minamoto Gender: Female Age: 10 Height: Around 140cm (about the same as Nobita or slightly taller) Appearance: The class idol with black hair (dark brown in the anime) tied in pigtails. Characterized by refined and lovely facial features. In the story, she enjoys the deep-sea camp wearing her favorite cute pink or red swimsuit (a modern, stylish design in the remake). Personality: Serious, kind, and very fond of cleanliness (she loves baths). While she gently watches over the group as the only girl, she is a strong-willed girl who shows more guts than anyone in a crisis. In this work, her boundless kindness and sincerity move the heart of the stubborn "Underwater Buggy," causing a miracle that drastically changes the story.

Takeshi Goda Gender: Male Age: 10 Height: Around 157cm (the largest among Nobita and his friends) Appearance: A sturdy, large build with a characteristic gorilla-like face. Usually wears an orange shirt and has an intimidating presence. During the deep-sea camp, he enjoys the world of the sea in a boisterous swimsuit. Personality: Normally a bully who lives by the motto "What's yours is mine," but during big adventures like this one, he displays "manliness" and "high initiative," becoming a more reliable friend than anyone. In the remake, he shows a passionate side by risking his life to shield El from an enemy attack, which becomes the biggest catalyst for El to reconsider his view of surface dwellers.

Suneo Honekawa Gender: Male Age: 10 Height: Around 135cm (the smallest among Nobita and his friends) Appearance: A pointed mouth and a characteristic hairstyle divided into three peaks. Wears well-tailored clothes befitting a rich kid (light blue or green shirts). During the deep-sea camp, he boastfully shows off the latest snorkel and stylish swimwear. Personality: Narcissistic, silver-tongued, and socially savvy. He is a sycophant who hides behind Gian's authority, but essentially he is a quick-witted intellectual who is good with machines and RC cars. While he is usually more cowardly than others and the first to run away, in moments of true crisis, he possesses the genuine friendship and courage to stand alongside Nobita and the others against hardship.

Underwater Buggy Gender: None (AI / Sentient Robot) Age: Newly manufactured (a latest-model secret gadget Doraemon bought from a future department store) Height (Size): About the size of a standard compact car, large enough for all five of Nobita's group to ride. Appearance: Characterized by a yellow body and cute, wide-open "eyes" that serve as headlights. An amphibious, futuristic, and compact buggy equipped with not just tires but also screws and underwater mechanisms. In the remake, the design is updated to a more modern and sophisticated stylish vehicle. Personality: Extremely cynical and foul-mouthed. He is always cheeky and rebellious toward Doraemon and Nobita, but he opens his heart completely and develops a deep attachment only to Shizuka, who treats him with kindness and sincerity as a "living being." Though usually cowardly and averse to fighting, when Shizuka is in danger, he overcomes his programming (fear) to demonstrate incredible courage and a spirit of self-sacrifice.