Historians often attribute Iran’s longstanding influence in Oman to a long and complex history that connects the two nations that straddle the Strait of Hormuz. For the purpose of this study, we will focus on the contemporary factors that have drawn the current Omani leadership to the regime in Iran, and highlight how they often conflicted with U.S. policy.

Sultan Qaboos assumed power in 1970 after he overthrew his father. The new sultan needed assistance quelling a rebellion, which had begun in 1962, in Oman’s southern Dhofar province. The United Kingdom provided training assistance to Qaboos’ troops, while Saudi Arabia, the UAE, and Kuwait provided financial assistance. However, it was Iran’s Mohammad Reza Shah, at Qaboos’ request, who sent troops in 1973. The revolt was put down in 1975, yet Iranian forces remained until 1977.

Regional dynamics changed dramatically after the February 1979 Iranian Revolution. Iran began to export its revolutionary ideology to the region, which threatened the security of the Gulf states. Oman, unlike its Gulf neighbors, embraced a strategy of engagement rather than hostility. In June 1979, Oman dispatched its undersecretary for foreign affairs to Tehran to ensure that preexisting agreements with Iran remained intact. (The Carter administration also initially sought a relationship with the new Iranian government, but that effort ended when Iranian students invaded the U.S. embassy that November, taking 52 American diplomats and citizens hostage. )

While drawing closer to Iran, Oman pursued a strategic relationship with the United States as an insurance policy. The sultanate signed the Oman Facilities Access Agreement on April 21, 1980, making it the first Gulf state to formalize defense relations with the U.S. This allowed the U.S. to use Oman’s Masirah Island air base later that year in the failed attempt to rescue the American embassy hostages in Iran.

When the Iran-Iraq War (1980-1988) erupted, Oman reportedly gave Iraq permission to use its bases, but withdrew the approval at the request of the U.S. Muscat then assumed a position of neutrality throughout the war. In 1981, Oman joined Saudi Arabia, the UAE, Kuwait, Bahrain, and Qatar in forming the Gulf Cooperation Council (GCC) – an alliance largely formed to deter Iran. However, Oman, along with the UAE, opposed Saudi Arabia’s plan for the GCC to completely sever ties with Iran. Muscat had the challenge of patrolling the Strait of Hormuz with its small navy, and believed it needed Tehran’s assistance. Throughout the war, Oman maintained diplomatic relations with both Iran and Iraq. It even reportedly hosted talks between the two sides in Muscat during the war. Sultan Qaboos also reportedly maintained personal ties with Iran’s supreme leader, Ayatollah Ruhollah Khomeini.

Meanwhile, Iran-backed Hezbollah began kidnapping Americans and Westerners in 1982. In an effort to obtain their release, the Reagan administration tried to engage Iranian pragmatists to no avail. After Hezbollah’s 1983 bombing of the U.S. marine barracks in Lebanon, the U.S. designated Iran a state sponsor of terrorism in 1984. This prohibited Tehran from receiving U.S. financial assistance and arms sales, and from purchasing dual-use items.

As tensions escalated between the U.S. and Iran, the U.S. Army Corps of Engineers reportedly spent $250 million in the 1980s modernizing Oman’s military bases at Masirah Island, Sib, Thumrait, and Khasab. Having successfully secured the trust of both sides, Muscat served as an intermediary between Washington and Tehran regarding the return of Iranians captured during naval skirmishes.

Following the end of the Iran-Iraq War and the death of Ayatollah Khomeini, U.S. administrations were open to improving relations with Tehran. “Goodwill begets goodwill,” President George H.W. Bush famously said to Iran in his 1989 inaugural address. But the U.S. remained alarmed over Iran’s efforts to acquire nuclear weapons and the means to deliver them, its support for terrorist organizations (especially Hezbollah, Hamas, Palestinian Islamic Jihad, and the Popular Front for the Liberation of Palestine-General Command), its potential to threaten shipping through the Strait of Hormuz, and its efforts to undermine the Israeli-Palestinian peace process.

During the 1990s, ties expanded between Oman and Iran. After Iraq invaded Kuwait in 1990, Oman joined the U.S.-led multinational coalition to liberate Kuwait. As it did in the Iran-Iraq War, Oman retained diplomatic ties with all the belligerents. Following Kuwait’s liberation, Sultan Qaboos and his foreign minister, Yusuf bin Alawi, both argued that Iraq was a greater threat to the region than Iran. They contended that the West should talk with Iran rather than isolate it.

In May 1990, the Omani oil minister visited Iran to explore joint ventures. Oman also reduced tariffs for Iranian vessels entering Omani waters. In 1993, the commander of the Omani navy traveled to Iran as part of a bid to ensure security in the Strait of Hormuz. In 1995, the commander of the Iranian navy toured a base in Oman. Cultural and trade agreements soon followed.

Washington remained concerned about Tehran’s nuclear program, however. In the 1990s, the U.S. persuaded Argentina, India, Spain, Germany, and France to prohibit the sale of nuclear technology to Iran. Nonetheless, Tehran received assistance for its Bushehr nuclear power plant and missile technology from Russia, Pakistan, China, and North Korea.

In 1995, President Bill Clinton issued Executive Order 12957, which barred U.S. firms from investing in Iran’s energy sector, and Executive Order 12959, which prohibited U.S. companies from trading with, re-exporting U.S. goods to, investing in, and financing loans for Iran. The Iran and Libya Sanctions Act of 1996 further barred non-U.S. businesses from investing more than $20 million in Iran’s energy sector.

Following the election of Iranian President Mohammad Khatami, President Clinton sent him a letter via Oman. The letter indicated that the U.S. had evidence of IRGC involvement in the 1996 bombing of Khobar Towers, which killed 19 American servicemen and wounded almost 400. However, the letter also expressed interest in improving relations with Iran. Clinton made public remarks as well about improving relations and eased some restrictions on Iran, though most U.S. sanctions remained in place.

The George W. Bush administration tried engaging with Iran, as well. After the 9/11 attacks, both Washington and Tehran supported the first post-Taliban government in Afghanistan. U.S. and Iranian envoys also held talks after the 2003 ouster of Saddam Hussein in Iraq. However, this cooperation soon collapsed. Iran provided weapons, training, and funding to the Taliban in Afghanistan and to Shiite militias in Iraq for their respective battles with U.S. and coalition forces.

All the while, international concern over Iran’s nuclear ambitions continued to mount. Following revelations in 2002 about Iran’s secret nuclear sites, Tehran agreed to the 2004 Paris Agreement, which required it to suspend uranium enrichment activities. This was short-lived, however, and Iran resumed uranium enrichment. In response, the United Nations sanctioned Iran in 2006, 2007, and 2008 for its nuclear and missile programs, imposed asset freezes and travel bans, and prohibited arms sales.

In 2007, the U.S. designated Iran’s Islamic Revolutionary Guard Corps (IRGC) for proliferation concerns, and the IRGC’s Quds Force for supporting terrorism. Washington also designated Iranian state-owned banks and persuaded more than 80 financial institutions to restrict their business with Iran. In 2012, the EU Council removed Iranian banks from the Society for Worldwide Interbank Financial Telecommunication (SWIFT) financial messaging service.

Omani officials, meanwhile, continually advised against sanctions on Iran, insisting that dialogue was the way to resolve conflicts. As a former Omani diplomat put it, “Iran is a big neighbor, and it is there to stay.” This position may have been driven as much by fear as a desire for peace. In the late 1990s, Oman uncovered a network of individuals in the country that was reportedly transmitting sensitive documents to Iran and potentially working to overthrow the Omani government in favor of an Islamist regime.

For decades, U.S. officials viewed the Omani-Iranian relationship as “largely non-substantive,” and therefore not a threat to U.S. interests. By 2008, however, American officials noted an increase in Omani-Iranian economic, political, and military relations.

Oman began taking a larger role in diplomacy on behalf of Iran in the 2010s. Following the storming of its embassy in Tehran in 2011, the UK downgraded diplomatic relations with Iran. Under a protecting power arrangement, Oman represented Iran’s interest in London until relations resumed in 2014. Similarly, Canada closed its embassy in Tehran in 2012, with Canadian Foreign Minister John Baird calling Iran a threat to global security. The following year, the Canadian Foreign Ministry named Oman “the protector of Iran’s interests in Canada.”

All the while, Oman has maintained close ties with the United States. In addition to signing a Free Trade Agreement with Washington in 2006, Oman has cooperated with the U.S. on terrorism-related issues and has participated in U.S. counterterrorism training programs. Washington and Muscat have renewed the Oman Facilities Access Agreement every 10 years, with the last renewal in 2010. This agreement allows the U.S. to request access to use Oman’s airfields in Muscat, Thumrait, Masirah Island, and Musnanah. Oman grants most requests and allows the U.S. Air Force to store equipment at these bases. In 2000, the U.S. funded the upgrading of the Musnanah base, which cost $120 million. Washington used these air bases during Operation Enduring Freedom in Afghanistan and in Operation Iraqi Freedom in Iraq.

Testifying in March 2018, Commander of USCENTCOM General Joseph Votel noted, “Oman’s strategic location provides CENTCOM with key logistical, operational, and contingency capabilities; it provides important access in the form of over 5,000 aircraft overflights, 600 aircraft landings, and 80 port calls annually.”

In March 2019, Oman signed an agreement to allow the U.S. military to access facilities and ports in Duqm and Salalah. Importantly, Duqm has the capacity to handle large ships and aircraft carriers. The ports also provide the U.S. military with access to overland routes that would enable American forces to reach the Gulf without transiting the Strait of Hormuz.