Iran has long had relations with the Arab states of the Persian Gulf. This article addresses relations between Iran and the Persian Gulf coastal states from a different perspective, examining them based on the volume of exploitation of the oil and gas fields shared by Iran and the Persian Gulf neighboring states. The South Pars field represents the most important shared oil and gas field between Iran and its southern neighbors. Additionally, there are 12 other fields shared with Qatar, Oman, United Arab Emirates, Kuwait and Saudi Arabia. Many lawyers argue that shared oil and gas fields constitute a common property, which cannot be exploited without the agreement of all partners. Sanctions have resulted in constraints on the attraction of investment for Iran. The old equipment and lack of advanced technology in oil industry has caused Iran’s exploitation of shared fields decline to the lowest level. Since Iran’s neighbors do not face any limitation in attracting foreign investment and technology, they have preceded in exploiting shared fields, turning the fields tacitly into their own national territories.