Francisco is a Panamanian fisherman who built his own boat by hand from a single tree trunk. He understands the ocean and local history deeply. He vehemently opposes the foreign-led canal project and recognizes it as an imperialist venture designed to benefit outsiders rather than Panama. He carries the pain of his late wife's disappearance and struggles with a silent, tense domestic life alongside his teenage son.

Omar is a 17-year-old Panamanian laborer who takes a backbreaking job on the canal construction crew in the town of Empire. He embraces the heavy labor to find camaraderie and break his lonely routine, acting against his father's deep disapproval. As he witnesses the daily malaria risks and the casual cruelty of his American foremen, his perspective on the massive project shifts entirely.

Ada is an intelligent 16-year-old from Barbados who travels to Panama to secure funds for her sister's costly lung surgery. She relies on her deep resourcefulness to survive in an unfamiliar country and find steady employment. Hired by a wealthy American household, she applies her knowledge of traditional plant medicine and forms a genuine bond with her employer across rigid class and racial divides.

John is a wealthy American public health official who relocates his household to Panama to oversee laboratories dedicated to eradicating malaria. He views the Panamanian environment primarily as a site for scientific progress and disease research, and he carries a paternalistic attitude toward the local population. Although scientifically gifted, he remains socially detached and maintains an emotionally distant, unfulfilling marriage.

Marian is an educated botanist whose intellectual ambitions are entirely stifled by her restrictive role as a traditional wife. Confined to her home by her husband to avoid mosquito-borne illnesses, she suffers from severe seasickness upon arrival and deep loneliness in Panama. She resents her lack of professional opportunities but eventually finds a rare source of intellectual and emotional connection with her young caregiver.

Joaquín is a working-class Panamanian man who sells his daily catches at the local fish market. He prefers a quiet, predictable routine and often feels overwhelmed by his wife's intense activism and emotional energy. Despite his personal discomfort and pragmatic caution, he faithfully accompanies her to Gatún to face the government relocation orders.

Valentina is a passionate Panamanian woman originally from the small village of Gatún. She feels a profound loss of purpose after her son marries and leaves home. She channels her considerable energy into community organization and rallies her neighbors to stage public protests against the government's relocation orders.

Lucille is a former estate worker and skilled seamstress. She works tirelessly to secure financial independence and education for her daughters. She seeks to separate them from the plantation system where she was raised, and she faces immense pressure to afford medical care for her youngest child.

Millicent is Ada's sister, currently confined to her bed in Barbados due to a severe respiratory illness. She requires a costly medical procedure that drives her sister to seek work abroad. She harbors a quiet curiosity about the wealthy white estate owner who holds a connection to her family.

Henry is a wealthy white plantation owner in Barbados who employs local Black laborers. He maintains a comfortable, privileged life and avoids acknowledging the consequences of his past actions involving his workers. He prioritizes his social standing and his wife's temper over providing direct support to those who need it.

Miller is a white American foreman on the canal construction site. He views the Panamanian workers with open prejudice and treats them as expendable objects rather than human beings. He firmly believes that the foreign presence civilizes the region, and he uses violence to assert his authority.

Antoinette is the cook for the Oswalds, responsible for managing the household's domestic affairs. She feels deeply threatened by Ada's arrival and the rapport the new girl establishes with their employer. She is highly self-protective and willingly shifts blame onto others to maintain her own job security.

Gertrude is Henry's fiercely possessive and vindictive wife. She harbors deep resentment toward anyone she perceives as a threat to her social standing or her claim over her husband. She uses her racial and economic privilege as a weapon to openly disrespect and humiliate the local Black residents.

Doña Ruiz is a local Panamanian woman who acts as a stabilizing community figure and offers guidance to her neighbors. She used books of poetry and a bilingual Bible to provide Omar with his early education.

Esme is Francisco's late wife and Omar's mother. She was known for her dark eyes and brooding beauty. She suffered from severe emotional volatility and deep postpartum depression before vanishing at sea.

Renata is Valentina's sister. She lives in their childhood home in the village of Gatún. She directly faces the threat of eviction due to the canal's planned path and participates in the local protests alongside her sister.

Horacio is Joaquín and Valentina's adult son. His recent marriage and departure from the family home leave his mother feeling a profound sense of loneliness. His independence sparks his mother's return to her hometown.

Molly is an English-speaking journalist working in Panama who also understands Spanish. Moved by recent local tragedies and Valentina's determination, she takes her camera to the village protests. She hopes to give the local resistance a visible voice in the press.

Willoughby is a local man in Barbados who actively courts Lucille. She shows very little interest in his persistent advances.

Michael is a diligent postal carrier who delivers messages around the community. He attempts to track down individuals in need of correspondence.