Wasini Island is located off the coast of southeast Kenya in the Indian Ocean. It sits approximately 75 kilometres (47 mi) south of Mombasa and is positioned 3 kilometres (1.9 mi) opposite the harbour of the village of Shimoni. The island measures roughly 7 kilometres (4.3 mi) in length and 3 kilometres (1.9 mi) in width.
The island is characterized by a lack of motorized vehicles, including cars, carts, or bicycles. Transportation across the land consists of footpaths made of sand or sharp old coral, with cargo moved by hand or via wheelbarrows with solid tyres. Travel over beaches is restricted to low tide due to the coral composition. While an airstrip existed in the lagoon south of the island during the British colonial period before 1963, only small fragments of tarmac remain today.