Abstract: The Greater Tunb, Lesser Tunb and Bu Musa islands are located between Bandar Lengeh in Iran and Dubai in the United Arab Emirates. They are of strategic value due to the location of the deepest point of the Persian Gulf in the middle of these three islands, because commercial ships and oil tankers must pass through this place to enter and exit the Persian Gulf. For this reason, they were in the hands of the world's naval power, namely Britain, for many years, and this country was able to maintain it until 1971. However, in the 1950s, between 1957-1958, other world naval powers, primarily the United States, decided that Iran, as an alternative country, would take responsibility for the security of the Persian Gulf and pave the way for the creation of OPEC. Therefore, in the 1970s, it was decided that the historical and political differences between the Persian Gulf countries would be resolved primarily between Iran and Bahrain. Therefore, Bahrain became independent by holding a referendum, and the world powers also took control of the three islands of Greater Tunb, Lesser Tunb and Bu Musa with the help of the Iranian Navy. Simultaneously with the deployment of Iranian forces on these islands, Britain was also required, according to the conditions set out in the Atlantic Charter, to withdraw all its forces from the east of the Suez Canal to the Indian Ocean 25 years after the end of World War II. Therefore, this country left the Persian Gulf after 200 years in 1971 and returned the Greater Tunb, Lesser Tunb and Bu Musa islands to Iran.