Skin of the Sea is based on the culture and traditions of the Yoruba people. The Yoruba people are an ethnic group of West Africa, primarily living in the southwestern part of Nigeria. In researching the book, Bowen relied on history texts and the work of Black scholars to flesh out the world, paying particular attention to the Ifá spiritual system of deities. In myth, Mami Wata is a water spirit common across West Africa, but some depictions show Mami Wata as a specific deity, of which Yemoja (present in Skin of the Sea) is one. In the 1400s, when Skin of the Sea is set, it was believed that Yemoja and Mami Wata followed slave ships, either destroying them or collecting the souls of the dead to bring back to Olodumare. Bowen was inspired by the collection of souls. She created the seven Mami Wata that Yemoja made to help with this task and used Simi’s choice to rescue a living boy as the event that jumpstarts Skin of the Sea’s major conflicts.

Bowen also borrowed from the culture of the Yoruba people. Yoruba people incorporated fractals, repeating patterns that suggest infinity, in their architecture and clothing.