Robinson is the deeply religious and highly educated patriarch of the stranded family. Drawing on his broad background in botany, biology, and engineering, he serves as the primary decision-maker and survival instructor for his wife and four sons. He approaches the daily challenges of the wild with calm pragmatism and a steady desire to recreate European comforts on the uninhabited island.

Elizabeth is the resourceful and practical mother of the stranded family. She manages the homestead, oversees crop planting, and frequently invents ways to make raw island materials useful for daily living. While she occasionally expresses worry over her husband's risk-taking, she remains a steady and grounding presence who anchors the family's domestic life.

At fourteen years old, Fritz is the eldest son and his father's most capable assistant. He eagerly takes on dangerous tasks and frequently accompanies Robinson on scouting expeditions into uncharted territory. He learns quickly, adopts his father's scientific curiosity about the island's wildlife, and consistently demonstrates physical bravery.

Twelve-year-old Ernest is the studious and introverted second son of the family. He prefers reading and staying close to the camp over undertaking strenuous or highly dangerous physical adventures. Despite his preference for mental pursuits, he actively participates in hunting and gathering when his father requires it.

Ten-year-old Jack is highly energetic, competitive, and constantly curious. He views the island's wildlife primarily as creatures to be captured, tamed, or ridden for sport. His boundless enthusiasm often leads him to act before thinking, though he works hard to match his older brothers in their physical feats.

At five years old, Franz is the youngest member of the stranded family. Due to his age, he spends most of the early island days staying safely behind with his mother while the older males explore. As he grows, he slowly takes on more responsibilities, such as helping to plant the family's vegetable garden.

Jenny is the daughter of a British colonel who taught her extensive wilderness survival skills. After a shipwreck leaves her stranded alone, she establishes her own treehouse and daily routines to stay alive. She possesses a resilient spirit and adapts quickly to the isolation of the natural world.

Turk is one of the two mastiffs left behind by the ship's crew. He proves immensely valuable to the family by fending off wild animals and assisting in daily hunts. He serves as both a protector and a working animal for the stranded group.

Knips is a young monkey adopted by the family early in their island stay. He becomes a fixture in the camp, occasionally serving as a test subject for unfamiliar foods, such as cassava bread, to ensure they are safe for human consumption.

Captain Littlestone commands the HMS Unicorn, a Royal Navy vessel tasked with searching for lost survivors. He represents the formal structure of European civilization and military authority.