The Shangani Post Office, or Old Post Office, was designed by the British architect J.H. Sinclair in the Saracenic style. It was inaugurated in 1906 and served as Zanzibar's main office until the end of the Sultanate of Zanzibar in 1964. It is a green and white two-story building, with a ground-level colonnade and an upper-level balcony flanking a central entrance.