Kilwa Kisiwani tide times

Kilwa Kisiwani is a tidal island off the coast of southern Tanzania, accessible by short boat crossing from Kilwa Masoko on the mainland. The island holds the ruins of the Kilwa Sultanate — a medieval Swahili city-state that, at its height between the 12th and 16th centuries, controlled one of the Indian Ocean's most significant trade routes: gold and ivory from Great Zimbabwe and the Sofala coast, traded north and east to Arabia, India, and China. The Arab traveller Ibn Battuta visited in 1331 and wrote that Kilwa was one of the most beautiful cities in the world.

That record is harder to square with the current ruins, but the scale of the remaining structures gives a sense of what was here. UNESCO inscribed the ruins as a World Heritage Site in 1981. 0 metres.

At low spring tide the tidal flats around the island's southern and eastern edges are exposed — a wide belt of sand and mud that extends 100 to 200 metres from the shoreline. The ruins closest to the shore, including sections of the Great Mosque's outer walls, sit just above the high water mark. At high spring tide the water reaches close to the base of the masonry in the lowest-lying sections.

The Great Mosque of Kilwa is the site's most substantial structure. Built in the 11th century and expanded significantly in the 14th and 15th centuries, it was the largest mosque in sub-Saharan Africa at the time of its peak use. The barrel-vaulted roof — a sophisticated construction technique for the period and geography — survives in the smaller Husuni Ndogo (Little Palace) section; the main prayer hall is now roofless, with the coral-rag pillars still standing in rows.

Husuni Kubwa (Great Palace), a 14th-century royal compound, is the largest single medieval building on the East African coast. Its audience hall, bathing pool, and trading area give a more complete picture of how the sultanate organised its commerce and court life. The Portuguese Fort Gereza, built between 1505 and 1510 after the Portuguese forced their way into the Indian Ocean trading system, was constructed over an earlier Arab structure.

The name Gereza derives from the Portuguese word for 'church' — the building was initially used partly for that purpose. It was subsequently used as a prison and customs post by successive powers and the walls are substantially intact. The boat crossing from Kilwa Masoko is 10 to 20 minutes depending on the vessel.

The crossing is possible at any tide, but at very low spring tide the channel is shallow in places and the local boatmen pick a route accordingly. The island itself has a small permanent community whose residents are the custodians of everyday life on the ruins site. The National Museums of Tanzania manage the archaeological heritage; entry fees apply.

Photography of the ruins is permitted without restriction. For tide photographers, the combination of coral-rag ruins, exposed tidal flat, and dawn light is a productive subject. The low water period around the spring low exposes the most foreground texture; sunrise timing relative to low water varies across the year and is worth calculating before the visit.

Predictions on this page come from Open-Meteo Marine, a gridded global ocean model. 3 metres on height — model-derived, not from a local gauge. The national authorities are the Tanzania Meteorological Authority (TMA) and Tanzania Ports Authority; the Zanzibar gauge provides the nearest long-term tidal reference.