Coraline is a perceptive and adventurous young girl who has recently moved into a large, divided house. She feels neglected by her busy parents and bored by her surroundings. This forces her to entertain herself by exploring the neglected garden, the abandoned tennis court, a dangerous boarded-up well outside, and the overgrown grass. Her curiosity naturally drives her to investigate the locked wooden drawing-room door in her family's flat, despite clear warnings from her eccentric neighbors. She has a strong independent streak and prefers practical, exciting things, expressing deep frustration when her mother buys her gray school uniforms instead of the bright, Day-Glo green gloves she desires.

The Other Mother is a mysterious and controlling figure who lives in a fully furnished flat identical to Coraline's on the other side of the drawing-room door. She physically resembles Coraline's real mother but is taller, thinner, has exceptionally pale skin, and possesses large black buttons instead of eyes. She creates an inviting, idealized version of Coraline's home, complete with delicious home-cooked meals like perfect roast chicken and a bedroom filled with animated toys. She heavily dotes on Coraline. She provides the constant attention her real parents lack and expresses an intense desire for the girl to stay with her permanently.

The Cat is a stray black feline that roams the overgrown grounds of the divided house, taking shelter in the surrounding woods. In the real world, it acts like a typical aloof animal. It consistently slips away and runs off when Coraline attempts to approach or pet it. However, it possesses the unique ability to travel effortlessly between different environments and can speak intelligently when outside the real world. The Cat maintains a smug and evasive attitude. It offers Coraline cryptic advice about the nature of the alternate flat while refusing to explain its own origins.

Miss Spink and Miss Forcible are two older, round women who live in the ground-floor flat with several aging Highland terriers named Hamish, Andrew, and Jock. They are retired theater actresses who constantly recall their past performances in grand Shakespearean plays. They frequently debate the merits of their respective stage portrayals of characters like Portia and Ophelia. They enjoy reading tea leaves to pass the time, keeping a jar of various odd trinkets in their home for fortune-telling purposes. They serve as friendly distractions for Coraline during rainy days. They offer her stale biscuits and vague warnings about danger.

Mr. Bobo is an eccentric older man with a large mustache living in the top-floor flat above Coraline's family. He claims to be training a complicated mouse circus to play tiny musical instruments, though he states the mice are not yet ready to perform for an audience. He consistently mispronounces Coraline's name as "Caroline" despite her frequent and annoyed corrections. In the alternate flat, his counterpart oversees a fully functional, unsettling act involving trained rats that sing strange songs and form pyramids. Both versions of the man inhabit flats that smell heavily of strange foods and pipe tobacco.

The Ghost Children are three mysterious, shadowy figures trapped in a small, closet-sized space. They originate from completely different historical eras, evident by their archaic manner of speaking. They have been in the darkness for so long that they have forgotten their own names and the specific details of their past lives. Cold, frightened, and weak, they reach out to visitors in the dark. They offer crucial warnings about the true, dangerous nature of their surroundings and the controlling entity that commands the house.

Coraline's mother and father are busy professionals who work from home. They are easily distracted by their computer screens. They frequently brush off Coraline's requests for attention, and they suggest she go play by herself, watch nature videos, or bother the eccentric neighbors. They provide for her basic needs but often overlook her specific desires. They routinely serve microwave mini-pizzas and complex leek stews that Coraline actively dislikes. Their constant busyness and focus on work leave Coraline feeling isolated, which drives her to seek out more interesting spaces in the house.

The Other Father is an alternate, idealized version of Coraline's real dad who resides in the flat beyond the drawing-room door. Like the Other Mother, he has large black buttons sewn onto his face in place of eyes. He is extremely cheerful, highly attentive, and eager to stop his work entirely to spend time with Coraline, presenting a sharp contrast to her real father. He exhibits no personal autonomy. He defers completely to the Other Mother's wishes and exists solely to help make the alternate world seem like a perfect, highly appealing paradise for visiting children.