Binti is a 17-year-old human student from the Himba people. She attends the intergalactic Oomza University after surviving a devastating attack on her transport ship, the Third Fish. The incident left her with severe trauma and physically transformed her hair into sentient tentacles called okuoko. She returns to Earth seeking a traditional pilgrimage to cleanse her feelings of guilt and isolation.

Okwu is a student at Oomza University and a member of the Meduse, a jellyfish-like alien species with a history of violence against humans. Large and physically imposing, it features a dangerous stinger and tentacles. It chooses restraint and cooperation over its species' traditional hostility, accompanying Binti on a highly controversial trip to Earth.

Binti's father is a respected master harmonizer and astrolabe maker in their Himba village. He suffers from severe arthritis that makes his precise mechanical work difficult. He operates under strict traditional views regarding gender and familial duty, viewing Binti's university education as a selfish abandonment of her responsibilities.

Auntie Titi is Binti's paternal grandmother and an elder among the Enyi Zinariya people. She is a botanist who lives in a desert cave decorated with blue rugs and homemade oils. She operates outside the rigid traditions of the Himba village and actively challenges her son's attempts to restrict Binti's independence.

Ariya is the priestess of the Enyi Zinariya people, a position she has held for over four decades. She lives an isolated existence in a cave located within a dried-up lake bed. She acts as a spiritual authority who guides others toward self-acceptance rather than demanding strict obedience or purity.

Mwinyi is a young man from the Enyi Zinariya community tasked with protecting travelers as they cross the dangerous Hinterland. He acts as a harmonizer, using distinct physical movements to communicate and defuse tension without violence.

Vera is Binti's older sister who resides in their Himba village. She holds deeply traditional views on marriage and communal obligation. She carries the heavy burden of supporting their ailing father's business and resents Binti for leaving those duties behind.

Dele is Binti's childhood best friend from her home village. He embodies the insular perspective of their local culture, viewing Binti's decision to travel into space as a rejection of their shared values.

Binti's mother is a traditional Himba woman who manages their ancestral home, the Root. She cares deeply for her daughter but struggles to understand her physical changes and unconventional life choices. She prefers to keep Binti insulated within village customs rather than allowing her to associate with outside groups.

Professor Okpala is the head of the mathematics department at the intergalactic university. She observes the strange behavior of Binti's ancient artifact and accommodates her student's unusual academic needs.

Professor Dema is a Khoush teacher instructing Protective Gear 101 at Oomza University. She harbors deep, historically rooted prejudice against the Meduse species, actively recreating ancient hostilities within her modern classroom.

Saidia Nwanyi is a psychological professional at Oomza University. She assists students in processing the psychological fallout of violence, specifically advising Binti against undertaking stressful travel too quickly.

Haifa is a student at Oomza University. She demonstrates everyday human prejudice by questioning Binti's physical changes, yet remains fundamentally helpful and good-natured toward her peer.

Truck Omaze is the mayor of Kokure, the city adjacent to Binti's village. He represents the local political establishment on Earth, formally welcoming human residents while pointedly ignoring alien visitors.