Surat Castle, also called the Surat Fort or Old Fort, is a 16th-century fortification on the bank of the Tapi River that served as the administrative and military heart of what was once India's most important trading port. Under Mughal rule in the 16th and 17th centuries, Surat was the gateway through which trade from the entire subcontinent passed to the Persian Gulf, Red Sea, and beyond. The fort controlled access to the river and the harbour.
The building visible today dates largely from the 1540s, when the Mughal governor rebuilt and expanded an earlier structure. The thick basalt walls, the watchtowers, and the river frontage give a clear sense of the city's former strategic importance. The castle is now open as a heritage site, with some museum sections inside. The surrounding area along the Tapi riverfront is being developed as a waterfront promenade. The best views of the fort are from the river.