The Persian Gulf is a marginal sea of the Indian Ocean connecting to the Gulf of Oman through the Strait of Hormuz. It forms Iran’s southern maritime border. Approximately 20 percent of global oil trade passes through the Strait of Hormuz, making the Persian Gulf a critical geopolitical waterway.

The Persian Gulf has been a major maritime trade zone since the Bronze Age, when Mesopotamian cities traded with the civilisation of the Indus Valley through Gulf ports. Dilmun, identified with modern Bahrain, was a major trading entrepôt. Persian, Parthian, and Sassanid dynasties controlled the northern shore and taxed the Gulf’s commerce. Arab Muslim expansion in the 7th century brought the Gulf’s shores into the Islamic world. The Portuguese arrived in 1507 and controlled key islands and ports for over a century. The Dutch, British, and French competed for influence from the 17th century onward, with Britain eventually establishing the dominant position that lasted until the 1960s and 1970s withdrawal from east of Suez.

The Persian Gulf today is the world’s most important oil export corridor. Approximately 17 to 21 million barrels of crude oil pass through it daily, representing roughly 20 percent of global petroleum trade. The Gulf is also a major LNG export route from Qatar. Iran controls the entire northern shore, giving it leverage over the Strait of Hormuz chokepoint. The Gulf hosts major US military bases in Bahrain, Qatar, Kuwait, and the UAE. The littoral states are divided between the Arab Gulf states aligned with the United States and Iran, which is in strategic competition with them. Iranian and Arab navies – particularly the IRGCN and US-backed Gulf state forces – maintain continuous presence in the Gulf.