Kino is the protagonist, and begins as a hard-working pearl diver. He has a wife, Juana, and a son, Coyotito. He is content with his life-style as a diver but is not wealthy until he discovers the pearl. After discovering the pearl, Kino gradually changes to become a completely different man. Though his family is still the center of his actions, he is also driven by his dreams of an escape from their poverty and desire give his son a better future. He quickly becomes obsessed with the material things that the pearl could bring. He is no longer content with his son being uneducated, or his family not being well-dressed. Instead of enjoying his family and their company, as he did in the beginning, he becomes discontent and always seeks more. He is also driven by his desire not to be cheated or slighted. Kino is named for the missionary Eusebio Kino.
Juana, Kino’s wife, is a secondary character. She is a loving woman who cares for her husband and son. Throughout the experience, she remains loyal to her family but also perceives the evil forces that the valuable pearl unleashes. For example, one night, she attempts to throw the pearl back into the ocean to bring back peace and happiness to her family, .
Coyotito is Juana and Kino’s infant son. He is their only child, so his parents do everything they can to protect him. Despite his parents’ love and effort, he is subject to much harm, both before and after the pearl is found.
The Doctor is an unnamed character who symbolizes wealth, greed and manipulation. Before the pearl is found, he refused to heal Coyotito because the family was poor, though it would have been easy for him to do so. However, after the family have found the pearl, he personally visits them at home and acts in a much friendlier manner to them than at their first meeting. This is all down to his greed and his anticipation of a large fee. He uses the natives ignorance to his advantage by lying about how to treat Coyotito. He uses his visit to try to discern from Kino's glances where in the house the pearl may be hidden. The doctor is in stark contrast to the family and is the beginning of the evil that will be unleashed by the pearl.
Juan Tomas, Kino’s brother, is wise and loyal. In the beginning, Juan Tomas warns Kino of the destruction that wealth may bring, demonstrating his love for his brother. When destruction does come, however, Juan Tomas does not turn away his brother but, instead, welcomes him in and protects him. He is one of the few characters that does not seek to gain from the pearl and shows he values the importance of family ties.
Apolonia is the wife of Juan Tomas, she helped her brother to protect and hide Kino.
The pearl dealers also demonstrate greed and manipulation. This time in an organised way from the cartel for which they work. When Kino tries to sell the pearl, the pearl dealers conspire to refuse to take the pearl for its actual price. Instead, they say it is almost worthless. They heighten the difference between what Kino wants from the pearl and what it actually brings. They force Kino to make the hazardous journey to the captal city to try and get a fair price for the pearl.
The thieves and trackers are shadowy figures who attack Kino from the moment it becomes widely known he has a precious object. Kino never recognizes who they are. They harass and then follow the family right to the end of the story. They force Kino to fight and kill to defend himself and his family and keep the pearl his own. In the final scenes, in which Kino is tracked by a posse, it is not clear in the text whether the group are thieves, or law enforcement officers hunting Kino for his killing of the man on the beach.