Norah is an English mother and devoted wife who studied at the Royal Academy of Music. Driven by the hope of reuniting with her husband and daughter, she channels her grief and musical talent into helping her fellow internees survive. She possesses a quiet defiance and practical resilience, volunteering for menial physical labor and organizing a voice orchestra to sustain the camp's cultural identity.

Nesta is a pragmatic, courageous nurse with the Australian Army who becomes the de facto matron for the surviving nurses after their ship sinks. Her small physical stature contrasts with her immense inner strength and willingness to place herself in physical danger to protect her colleagues. Drawing on her professional training, she focuses on the practical necessities of survival, implementing sanitation and medical protocols with minimal supplies.

Ena is Norah's younger sister, initially characterized by her fear and dependence on her husband and sister. After surviving the shipwreck with Norah, she begins to find new purpose by adopting a maternal role toward a young orphaned girl. She serves as Norah's closest confidante and emotional anchor throughout their imprisonment.

Margaret is a missionary teacher with nursing training who functions as a spiritual anchor for the interned women. She leads by gentle, unwavering example, establishing church services and encouraging the women to find hope in the natural world. Her musical collaboration with Norah helps transform the internees' suffering into expressions of communal strength.

Vivian, affectionately known as Bully, is a knowledgeable and good-humored Australian Army nurse who survives a horrific execution on Radji Beach. The traumatic ordeal leaves her withdrawn but establishes her as a crucial witness to wartime atrocities. She carries the heavy burden of her secret testimony while working alongside the other surviving nurses.

Mrs. Hinch is an American woman married to an Englishman, defined by her formidable diplomacy and administrative competence. She organizes the camp into a functioning society by setting up committees and work rotas to manage daily life. She confronts the Japanese commandants with directness and courage to advocate for the prisoners.

Captain Miachi is a Japanese commandant who oversees the women's internment camp at Irenelaan. He enforces arbitrary rules and harsh punishments, demonstrating the systematic cruelty of the military occupation. His attempts to coerce the nurses into serving his officers spark widespread resistance among the prisoners.

Captain Seki is a Japanese commandant who takes over the administration of the internment camp. He exhibits a callous disregard for the prisoners' lives, manipulating their rations and enforcing brutal punishments for minor infractions. His demands clash directly with the women's efforts to maintain their cultural identity.

John is Norah's husband, whose severe illness at the start of the evacuation adds to the family's precarious situation. Separated from Norah shortly after their capture by the Japanese, his survival and location remain an ongoing question. The hope of reuniting with him becomes the primary driving force behind Norah's will to endure.

June is a five-year-old girl who becomes separated from her family during the sinking of the HMS Vyner Brooke. She acts as a focus for the maternal instincts of the women around her, giving them an immediate reason to maintain their humanity. Her simple childish needs ground the women during extreme deprivation.

Betty is a dedicated Australian Army nurse who survives a harrowing ordeal at sea involving Japanese motorboats and a mangrove swamp. She plays an active role in camp life, contributing to the camp newspaper committee and helping maintain morale. She remains a steadfast member of the tight-knit group of nurses supporting Nesta James.

Sally is Norah and John's eight-year-old daughter, who is sent away on a ship to Australia with her aunt to escape the Japanese invasion. Her distress at being separated from her parents haunts Norah, driving her mother's will to survive the internment camps.

Ah Fat is an interpreter who acts as the primary liaison between the Japanese commandants and the interned women. While he serves as a tool of the oppressive regime, he occasionally shows brief flickers of humanity when delivering orders or interacting with camp leaders.

Tante Peuk is an Indonesian woman forced to sexually service the soldiers. Because of her tragic position, she occasionally gains access to extra food, which leads to a complex transaction and an eventual bond of mutual care with Norah.

Sister Catherina is a Dutch nun interned alongside the other women. She offers practical assistance to the camp, leading repairs on storm-damaged huts and supporting the nurses when medical conditions become dire.

Audrey is a resourceful friend of Norah's who helps construct vital sanitation systems out of scavenged materials to combat the spread of disease in the camps. She also assists Norah in the grim task of preparing the camp cemetery.

Dr. McDowell is a fellow internee who serves as the official representative for the prisoners. She coordinates the women's responses to the Japanese officers and works alongside Mrs. Hinch to protest the abuse of hospital patients.

Matron Olive Paschke is a senior leader among the Australian Army nurses. She organizes emergency teams and maintains discipline during the chaotic evacuation and subsequent shipwreck, earning the deep respect of her subordinates.

Matron Drummond is a senior nursing leader who helps direct the evacuation drills aboard the Vyner Brooke. She survives the initial sinking only to face capture by Japanese soldiers alongside Vivian Bullwinkel and other survivors.

Ken is Ena's husband, who chooses to remain in Singapore to care for his aging parents-in-law while his wife and the Chambers family flee. His absence weighs heavily on Ena, who continuously fears for his safety.