This article provides a historical account of Iran's legitimate sovereignty over the Tunb Islands and Bumusa Island in the Persian Gulf, tracing the origins of the dispute to flawed Qajar-era territorial administration practices and British imperialist ambitions to dominate the region. It chronicles how Britain, either directly or through backing its local puppets, hostilely occupied the islands from the late 19th century to safeguard British interests in the region, vehemently opposing any Iranian foothold through diplomatic pressures and threats of military force. Diplomatic negotiations between Iran and Britain in 1928-29 reached an impasse due to Britain's intransigent stance denying Iran's historical sovereignty. Subsequently, under Britain's Labour government from 1929 onwards, it continued thwarting reasonable resolution, cynically backing the territorial claims of British-protected Arab Sheikhdoms descended from deputies who had previously administered the islands on Iran's behalf. The article asserts this neo-colonial policy was inherited by Arab nationalist voices challenging Iran's ownership over the islands in more recent decades. Ultimately, Iran's sovereignty over its three islands was restored on November 30, 1971, following three years of negotiations with Britain.