The Islamic Republic of Iran, excluding its islands, has 1,400 kilometers of coastline along the Persian Gulf, the longest among the countries in the region. Including the Iranian islands, the length of Iran's coastline in the Persian Gulf extends to approximately 1,800 kilometers. These islands play a crucial role in expanding the territorial sea of Iran. This feature allows Iran to better safeguard its security in the Persian Gulf and, according to international laws, exert greater control over navigation in this body of water. Additionally, this extensive territorial sea enables Iran to more broadly exploit the fossil resources of the Persian Gulf. Consequently, other actors in the Persian Gulf have consistently sought to challenge Iran's sovereignty over these islands. This research, using a descriptive-analytical method, explains the importance of the three islands in enhancing the maritime power of the Islamic Republic of Iran in the Persian Gulf and their role in strengthening the national security of Iran.