Louise is Henry Scobie's wife, who is devoutly religious and has a strong interest in literature and poetry. She is pragmatic and struggles with unhappiness in her colonial surroundings while trying to maintain her marriage.

Wilson is a British counterintelligence agent focused on observing the security administration and Scobie. He has literary interests and romantic ideals, but his lack of confidence and practical sense lead to complex personal entanglements.

Father Rank is an eccentric and talkative priest with great insight into human nature. Despite his role within the Church, he often presents unorthodox views that question institutional religious doctrines.

Helen is a young shipwreck survivor and widow with practical concerns about her future. She becomes involved with Scobie and navigates her relationships with youthful recklessness and a lack of religious conviction.

Yusef is a Syrian involved in the colony's black market, known for his business dealings and lack of remorse for his actions. His relationship with Scobie becomes increasingly complex as the story unfolds.