With the increasing hegemony of Britain over the Persian Gulf in the late 18th century and the early 19th century made it evident for the exclusion of opponents of this country in the region. At the same time, Britain became the main enemy since the Qasimi dynasty also called Qawasim, started expanding its naval fleet in the Strait of Hormuz, both for political and commercial reasons. The British Navy tried many times to destroy Ras al-Khaimah that was the main base for the Qawasim. Two such attacks carry greater significance, which were launched in 1809 and 1819. Their importance is due to the fact that the 1820 treaty played an important role in the history of the Persian Gulf as well as in the formation and independent Arab emirates off the southern coast of the Persian Gulf. In this article, with the historical studies approach, we seek to study the conflict over Ras al-Khaimah between 1809 and 1819 as well as the impact of two wars of 1809 and 1819 and subsequent agreement on historical transformation of the southern coast of the Persian Gulf and the fate of inhabitants there.