Prior to 1884, Zanzibar and the mainland used Riyal coins issued by the sultan of Zanzibar under the Sultan of Oman.
After 1884, Zazibar uzed a combination of coins. There were the Maria Theresa thaler coins, the Indian Rupee Coins and the Indian Rupees.
Maria Theresa Thaler
Indian Rupee Coins
After the end of world war 1, Zanzibar used the East African coins just like the other her neighboring states under the british rule:kenya Uganda and Tanganyika.