Hannah is a young Jewish girl living in Nazi-occupied Berlin. With blonde hair and blue eyes, she frequently passes as a member of the "pure" class, a trait that complicates her understanding of identity and nationality. She is perceptive and deeply attached to her family, surviving the hostile environment of her city by exploring its streets alongside her closest friend.

Anna is a twelve-year-old girl living in Manhattan who looks remarkably like her great-aunt. She carries the emotional burden of caring for a mother paralyzed by grief while desperately yearning to know the father she never met. When a mysterious package arrives from Cuba, it sparks her determination to uncover her family's hidden history.

Alma is Hannah's mother, a woman who fiercely guards her identity as a German citizen despite the hostility directed at her family. She is highly cultured, speaking four languages fluently, and presents herself with striking elegance in public. Privately, she struggles with severe depressive episodes that force her to retreat from her family.

Anna's mother is a former literature professor at Columbia University who has completely withdrawn from society following the disappearance of her husband. She rarely leaves her bedroom, turning it into a refuge from reality. The sudden arrival of photographs from Cuba briefly revives her energy and prompts her to travel.

Leo is a tall, energetic twelve-year-old boy and Hannah's closest companion in Berlin. Living in difficult conditions in a boardinghouse with his father, he maintains a sharp awareness of the dangers surrounding them. He is deeply protective of Hannah and optimistic about starting a new life together across the ocean.

Max is Hannah's father and a respected university professor facing intense persecution in Berlin. He works tirelessly behind the scenes to secure his family's escape, making desperate bargains and acquiring emergency contingencies. He values education, culture, and the safety of his wife and daughter above all.

Louis is Anna's missing father, a quiet and cultured man whose disappearance casts a long shadow over his family. Raised by his aunt in Havana before moving to New York, he possessed a deep love for literature, classical music, and international cinema. His mysterious history in Cuba serves as the catalyst for his daughter's journey of discovery.

Diego is a talkative and energetic local boy in Havana who quickly attaches himself to Anna. He serves as her informal guide, showing her the streets and rooftops of the city. His lively nature offers Anna a sense of freedom and companionship in an unfamiliar environment.

Hortensia is a local woman employed to help in Hannah's household in Havana. She embodies the vibrant, expressive culture of Cuba, actively embracing sunlight, music, and local traditions. Her warmth and cooking provide Hannah with comfort during difficult transitions.

Gustavo is Hannah's younger brother, born after the family's turbulent ocean crossing. Unlike his European relatives, he fully absorbs the local culture of Havana, preferring its music, language, and expressive emotional style. As he grows, his political interests further distance him from his family's reserved traditions.

Julian is a law student at the University of Havana who takes an immediate, intense interest in Hannah. He is charming and persistent, finding symbolic meaning in the shared pronunciation of their names. He provides Hannah with a temporary sense of hope and romantic connection during a shifting political climate.

Mr. Levin is an older man living in Anna's New York apartment building. Accompanied by his dog, Tramp, he acts as a stabilizing presence in Anna's daily routine, offering her gentle encouragement and practical advice when her home situation becomes overwhelming.

Tramp is Mr. Levin's dog. The animal provides a small but necessary source of comfort and normalcy for Anna during high-stress mornings.

Herr Braun is an elderly, deaf man living near Leo in Berlin. Labeled an "Ogre" by the children, he shouts slurs at them, though they regularly sit near his window simply to listen to his radio for news broadcasts.

Herr Martin is Leo's father, a Berlin accountant whose professional practice evaporates due to discriminatory laws. He attempts to secure his family's safety by arranging passage to Cuba, bearing the immense stress of a rapidly deteriorating social position.

Captain Schröder commands the MS St. Louis, the ship carrying refugees to Cuba. He treats his passengers with profound dignity and hospitality, creating a safe atmosphere aboard his vessel that sharply contrasts with the hostility the families left behind.

Mrs. Berenson is an elderly survivor of the MS St. Louis voyage living in modern-day New York. Retaining her German accent, she enthusiastically studies the historical photographs Anna brings, though the images eventually trigger overwhelming emotional reactions.

Walter is a young boy traveling aboard the MS St. Louis. He wears clothing that hangs loosely off his frame and spends his time racing through the ship's corridors, eagerly passing along news and rumors to the other children.

Kurt is a young passenger on the ocean liner who wears an enormous hat and jacket. He joins the other children in discovering the vessel's hidden rooms, temporarily enjoying a sense of freedom on the open sea.

Ines is a young passenger on the MS St. Louis who initially projects a snooty attitude. She invites Hannah to a pristine tearoom and boasts about her family's future travel plans to New York.

Mr. Adler is an eighty-seven-year-old passenger on the refugee ship. Exhausted by the political upheaval in Germany, he finds himself bedridden during the voyage, lacking the physical and emotional strength to start a new life.

Mrs. Adler is an elderly woman traveling aboard the MS St. Louis. She serves as a pragmatic voice of reason, noting that refugees have very few choices when forced to flee their homes.

Mr. Moser is a passenger deeply affected by the bureaucratic delays preventing their disembarkation in Cuba. The profound uncertainty of their situation pushes him into a severe state of psychological distress.

Mrs. Moser is a distressed passenger on the refugee ship. She looks to the more influential families aboard for answers, hoping someone can intervene and provide a solution to her husband's severe despair.

Esperanza is Hortensia's sister, who eventually works at Hannah's pharmacy. She possesses a natural gift for customer service, readily listening to patrons' personal stories and creating a welcoming atmosphere.

Rafael is Esperanza's son. He initially works by delivering goods for the local pharmacy, but his religious affiliation eventually makes him a target for the island's new political regime.

Señor Dannón acts as the legal counsel for Hannah's family in Cuba. He manages their affairs and delivers significant news from Europe, continuing his services until his own practice is absorbed by the state.

Viera is Gustavo's wife, a young woman deeply committed to the revolutionary changes sweeping through Cuba. She prioritizes her political work and government duties over traditional domestic life.

Catalina is a woman of African and Spanish descent who manages Hannah's household in later years. She fills the property with sunflowers and herbs, offering grounded, practical advice about accepting life's hardships and moving forward.