A twelve-year-old Jewish boy from Germany and one of the protagonists of the book. Josef is eager to grow up and feels a strong sense of responsibility to take care of his family. Josef is quick-thinking and has a clear moral compass. He sees the Nazi forces in Germany as ruthlessly unfair and objects strongly to being held in the harbor of Havana, forbidden to leave the ship. His sense of responsibility and manhood leads him to help the mutineers aboard the St. Louis.
An eleven-year-old girl from Havana, Cuba, and one of the protagonists of the book. Isabel is devoted to her family and wants to keep them together. She is brave and takes the initiative in helping them leave Cuba. She has a playful nature and plays the trumpet, but her girlhood dreams are dashed by dire circumstances. Although she is a gifted musician, she struggles to hear the clave, a rhythm underlying all Cuban music, which all her family members can feel. Isabel worries that being unable the find the clave means she is not fully Cuban.
A twelve-year-old boy from Aleppo, Syria, and one of the protagonists of the book. In order to feel safe living in a war zone, Mahmoud finds ways to avoid attracting attention, in school and while walking the streets of Aleppo. On his journey to Germany, he begins to realize that being “invisible” only sometimes keeps him safe. Sometimes he needs to risk being noticed so that people who want to help his family see that they need help.
Josef’s father, who is sent to a concentration camp. Although he is released and joins his family on their journey out of Germany, his experience in the camp leaves him severely psychologically damaged, terrified of any engagement with the outside world. Aaron fears that the Nazis will come for him again, and hopes that he would die rather than be captured.
Josef’s mother, who works throughout the book to keep her family safe. Rachel’s plans are disrupted by the ways the trauma of the camp has changed Aaron, her husband, and she comes to depend on Josef for help managing him on the ship. Despite many misfortunes, Rachel keeps hope alive and continues to make plans for their survival.
Ruth Landau/Ruth Rosenberg
Josef’s six-year-old sister. Later, as an old woman, she and her husband host Mahmoud and his family when they come to Germany.
Mariano Padron, Isabel’s grandfather. A policeman when the Landaus arrive in Cuba aboard the St. Louis, Lito saves Aaron Landau’s life when he jumps from the ship. Lito has a sense of humor and a small sense of patriotism, not wanting to leave Cuba for the United States.
Isabel’s twelve-year-old neighbor and best friend, who wants to be a professional baseball player.
Mahmoud’s ten-year-old brother. Waleed does not remember life before the war. The bombing of the family’s apartment leaves Waleed psychologically damaged and numb to the outside world.
Mahmoud’s mother, a former nurse. Fatima becomes obsessed with finding her baby, Hana, after they are forced to send the child on another refugee boat.
Mahmoud’s father, an engineer who tells jokes to try to keep the family’s spirits up. Until he is beaten in a Hungarian refugee camp, Youssef strongly believes he can get his family to Germany.
Mahmoud’s sister, a baby, who is separated from the family.
Iván’s father, who builds the boat they use to escape Cuba.
Isabel’s father, also called Papi. Papi is argumentative and cautious. He often argues with Rudi Castillo over the best course of action.
Teresa Padron de Fernandez
Isabel’s mother, also called Mami.
Iván’s older brother, a policeman.
Luis Castillo’s girlfriend, also a police officer.
Iván’s mother, a lawyer.
The captain of the St. Louis, who sympathizes with the refugees and promises not to take them back to Germany.
A steward on the St. Louis and the Nazi Party Leader aboard the ship.
A passenger on the St. Louis who leads an attempted mutiny.
Renata and Evelyne Aber
Sisters travelling alone on the St. Louis, coming to meet their father in Cuba.
An elderly man, the husband of Ruth Landau, who hosts Mahmoud’s family in Germany. He is a survivor of the Holocaust.
A friend of Lito’s who trades gasoline to Isabel in exchange for her trumpet.
A car dealership owner who helps Mahmoud’s family in Turkey. Nasseer was a child refugee himself, from Palestine.
Mahmoud’s best friend, a Shia Muslim, part of the minority in Syria.
Josef’s best friend at school, who joins the Hitler Youth.
Josef’s teacher, who uses him as an example of Jewish facial types.
Renata and Evelyne’s father, who lives in Cuba.
Petty Officer Jockl
The man who leads the children on their tour of the St. Louis.
Lito’s brother, who lives in Miami.