The shell collector is a 58-year-old blind malacologist living in isolated retirement on a remote island in the Lamu Archipelago of Kenya. Having lost his sight as a boy, he learns to identify shells entirely by touch, finding comfort in the predictable patterns of marine life rather than in human society. He fiercely protects his daily routines and resents the outside world's intrusions onto his reef.

Nancy is an American traveler from Seattle who abandons her family to search for spiritual purpose across the globe. Identifying as a neo-Buddhist, she speaks rapidly and openly about her personal problems to anyone who will listen. Her arrival on the island and severe malarial illness interrupt the shell collector's carefully maintained isolation.

The mwadhini is the man who proclaims the Islamic call to prayer in the nearby town of Lamu. He is an individual of deep faith who interprets natural events as elegant signs of Allah's will. When his daughter contracts malaria, he travels to the island convinced that the shell collector has the divinely appointed ability to cure her.

Josh is the shell collector's adult son and a Peace Corps volunteer. Characterized by his generosity, he acts as a distinct contrast to his father's isolationist tendencies. He actively seeks to help others, quickly taking responsibility for three orphaned boys camping near his father's property and teaching them about the ocean.

The Jims are two overweight reporters from a New York tabloid who travel to Kenya to interview the shell collector. Operating as a singular unit, they represent the chaotic, noisy outside world crashing into the island's peaceful ecosystem. They remain distinctly out of their element in the rugged natural environment, focusing entirely on their story rather than the delicate reef around them.

Seema is the daughter of the mwadhini from Lamu. She falls desperately ill, prompting her family to seek out the shell collector for an unconventional cure. Her situation brings a fresh wave of unwanted attention to the island, further testing the collector's desire for solitude.

Dr. Kabiru is a medical professional from the town of Lamu. He provides conventional medical assistance to those who wash up on the island, serving as a practical bridge between the isolated shell collector and the established community on the mainland.

Tumaini is the shell collector's loyal dog. Living on the isolated Lamu Archipelago reef, Tumaini serves as the protagonist's primary companion during his daily routines of walking the beach and searching the tide pools for shells.