The 16th century Kongo Mosque is located at the Northern tip of Diani Beach, where the Kongo river flows into the ocean. It is the last remaining ancient Swahili structure in Diani.
Diani beach is about 17 kilometers (11 mi) long, from the Kongo river to the north and Galu beach to the south (the southern point of reference is an old Baobab tree). Diani is one of the most prominent tourism resort areas of Kenya. The indigenous people of the area are Digo, one of the nine ethnic communities known as the Mijikenda. Today the area includes Kenyans of various ethnicities who have migrated to Diani, drawn by the promise of a tourism-related economy. With a population of over 100,000 inhabitants, the Diani/Ukunda urban area is one of the largest at the Kenyan coast and forms part of the larger Mombasa metropolitan region.
A small airstrip – Ukunda Airport – is located between the beach area and the Mombasa-Lunga Lunga road. The water remains shallow near shore, with some underwater sandbars near the surface which allow wading with a clear view of the sandy bottom. Inland from the beach, there is extensive vegetation, including numerous palm trees that cover the coastal areas, unlike the dry acacia trees of the mountainous Kenyan Highlands. The Mwachema River flows into the sea at Diani Beach.