With a population of over 7,402 people,⁠[1] Abu Musa Island is part of Hormozgan Province. It consists of a central district along with the Siri and Tonb islands rural districts.⁠[2] The island covers an area of 12.8 square kilometers. Its name comes from two words: “ Bu” (short for “ Bum”, meaning land or territory) and “ Musa”, a person’ s name. It appears that an Iranian man named Musa lived on and ruled the island before the Arab invasions.⁠[3]
Abu Musa Island is located almost in the middle of the Persian Gulf, between Bandar Lengeh and Sharjah. It is 45 kilometers from Siri Island, 46 kilometers from Greater Tonb, and 44 kilometers from Lesser Tonb.⁠[4] Because each of the islands — Tonb, Qeshm, Farur, Abu Musa, and Siri — has a twelve-nautical-mile territorial sea, and the distances between them are all less than the combined breadth of two such zones (24 nautical miles), Iranian maritime law treats the waters among them as internal waters under full Iranian sovereignty.⁠[5]
All ships passing through the Strait of Hormuz sail between the Iranian islands of Greater Tonb, Farur, Abu Musa, and Siri. Drawing an imaginary line that runs alongside these islands, including Abu Musa, clearly shows their geostrategic importance in defending international shipping in the Strait of Hormuz and protecting Iran’ s southern coasts and ports. Because of its proximity to the Strait of Hormuz, Abu Musa is an ideal location for military equipment and serves as a suitable base for naval operations across the Persian Gulf. The island functions as an observation and control platform — like an unsinkable, fixed aircraft carrier — playing a vital role in the defense of the Persian Gulf and the Sea of Oman.⁠[6]
Historically, Abu Musa was associated with various mainland regions such as Fars, Kerman, and Makran, before coming under the authority of what is now Hormozgan Province. Around 1891, the island was under Iranian authority, as Portuguese control in the region had ended long before, in 1622. In June 1904, however, the British raised their flag on Abu Musa and Greater Tonb, an act that met with strong Iranian opposition. Britain later tried to hand Abu Musa over to the Sheikhdom of Sharjah, but this too was met with fierce resistance from Iran.⁠[7] On November 30, 1971, units of the Iranian Navy landed on the shores of Abu Musa, Greater Tonb, and Lesser Tonb, restoring and consolidating Iran’ s sovereignty over the three islands.⁠[8]
In early 1980, following the start of border violations and Iraqi military movements, the Iranian Navy implemented the “ Derafsh” defensive plan in the Persian Gulf.⁠[9] In response to Iraqi threats to attack Abu Musa, Greater Tonb, and Lesser Tonb— and amid indications that some Persian Gulf states might cooperate with Baghdad— a company of naval commandos and a company of airborne troops were deployed to the three islands. Two BH-7 hovercraft were also transferred from Kharq Island to Bandar Abbas, along with logistic vessels, to support the units stationed there. Later, with the formation of the Marine Infantry Unit in 1980, responsibility for the defense of the island was handed over to that unit.⁠[10]
In early 1980, it was announced that Iraq intended to hold a naval and amphibious exercise in the Umm Qasr area for three days starting on April 5.⁠[11] In response to this maneuver and to Iraq’ s military activities in coordination with the UAE regarding the three islands, Iranian authorities decided to conduct a drill as part of the Derafsh Plan to defend Abu Musa, Greater Tonb, and Lesser Tonb. Subsequently, the largest naval exercise since the victory of the Islamic Revolution, named Joint Combat Exercise 59-1, was held from May 16 to 20, 1980, with the participation of all three branches of the Iranian Army. The exercise included eleven vessels, one helicopter, two hovercraft, a company of naval commandos, a company of paratroopers from the 55th Airborne Brigade of the Army Ground Forces, four F-4 Phantom aircraft, and four C-130 transport planes.⁠[12]
After Iraq invaded Iran on September 22, 1980, and following Saddam Hussein’ s claim that he had enough forces to occupy the three islands, units of Iranian naval commandos were sent to the islands. They signaled their presence through shows of force and military exercises in October 1980. Because the Iraqi army was heavily engaged in Khuzestan, the issue of occupying the three islands was put on hold. Because of the urgent need for troops on the Khorramshahr front, most naval commando units were redeployed there, leaving only a small protective detachment on Abu Musa.⁠[13]
As the Tanker War intensified in the Persian Gulf and Iran moved to retaliate against Iraqi attacks,⁠[14] Iranian helicopters began operating from Abu Musa Island in May 1984 to strike Iraqi oil tankers.⁠[15] In 1987, the Islamic Revolutionary Guard Corps (IRGC) Navy also deployed forces to the island.⁠[16] To counter Iraqi air strikes, nine anti-aircraft guns were deployed to Abu Musa in late 1986.⁠[17] After the war, the IRGC units left the island in November 1988.⁠[18]
From 1981 to 1992, the UAE made no claims regarding Abu Musa.⁠[19] In August 1992, the UAE sent around ten people to the island, claiming they were teachers, but Iranian authorities did not allow them to enter the island.⁠[20] Iran stated that documents found on their boats indicated they intended to engage in espionage.⁠[21] In another incident that same month, Iran blocked an Emirati ship carrying 104 unauthorized passengers from entering the island. The UAE’ s goal in such actions was to alter the demographic composition of Abu Musa in its favor.⁠[22] In response, Iran decided to strengthen the island’ s defensive positions. A unit of Army Marines was transferred from Manjil to Bandar Abbas and then deployed to Abu Musa. This unit was named the Islands Defense Unit. As more forces were added, Greater Tonb and Lesser Tonb were also brought under its defensive coverage. Siri Island was included in the plan due to its strategic importance, oil facilities, airport, and suitable runway for heavy aircraft. Following these measures, the sheikhdoms that had suspended relations with Iran backed off from their military threats and once again expressed readiness to restore ties.⁠[23]
From 1995 onward, following the division of maritime missions, responsibility for protecting the Persian Gulf was assigned to the IRGC Navy.⁠[24] IRGC marine infantry brigades were later stationed on the three islands, where they remain responsible for their defense.⁠[25]