Mombasa Coast

Kenya's Indian Ocean coast runs for approximately 480 kilometres between the Tanzanian border in the south and the Somali border near Kiunga in the north. For most of this length, a fringing coral reef runs 500 metres to 2 kilometres offshore, creating a sheltered lagoon inside the reef even when the southeast trade winds — the kusi, blowing from May to October — drive heavy weather on the outer reef face. Mombasa, Kenya's second city and main port, sits on a coral island at the centre of this coast, connected to the mainland north and south by bridges and a short ferry crossing. The tidal regime here is semidiurnal with strong diurnal inequality. At the Kenya Ports Authority gauge in Mombasa harbour, spring range typically runs 3.2 to 3.8 metres; neap range around 1.7 metres. This is the authoritative reference point for the Kenyan coast — the KPA gauge has a long continuous record and is used by Kenya Ports Authority for port operations, by KMFRI (Kenya Marine and Fisheries Research Institute) for reef research, and by the Kenya Meteorological Department for coastal flood monitoring. The fringing reef creates a particularly dramatic tidal transformation: at low water the reef flat may expose for 1 to 2 kilometres from the waterline, with seagrass beds and coral rubble visible across the lagoon floor; at high water the same lagoon is a flat, clear sheet of water 1 to 2 metres deep. Diani Beach, 20 kilometres south of Mombasa, is the most developed stretch of the south coast, with hotels, kite schools, and a well-established dive industry working the reef. Nyali is the closest northern beach suburb, historically the site of the first coastal hotels in Kenya. Both sit inside the reef system and experience the same tidal rhythm, though with slight timing differences due to local bathymetry. Tide predictions for Mombasa Coast locations on TideTurtle come from Open-Meteo Marine, a gridded global ocean model, with a typical accuracy of plus or minus 45 minutes on timing and 0.2 to 0.3 metres on height. For authoritative tide times, the Kenya Ports Authority publishes official tide tables for Mombasa.