The Red Sea region and the Bab el‑Mandeb Strait, as vital transit routes for a large share of global energy and goods, rank among the world’s most strategic maritime chokepoints. Since the outbreak of Yemen’s crisis in 2011, this corridor has become a contested arena for Iran, Saudi Arabia, the United States, and Israel. This study addresses the question: What objectives does Iran pursue in the Red Sea, and to what extent has its strategy secured Iranian national security against geopolitical threats? It hypothesizes that Tehran’s policy is fundamentally defensive—aimed at forestalling external threats, extending strategic depth, and deterring hostile coalitions led by Riyadh, Washington, and Jerusalem—and that these measures have substantially enhanced Iran’s deterrence. Employing defensive realism as its theoretical framework, which emphasizes state security over expansionism and casts threat balancing as a core strategy in an anarchic system, the research adopts a qualitative–descriptive approach based on document analysis. Primary sources include official Iranian communiqués, international agency reports, and peer‑reviewed scholarship. Findings reveal that, by forging alliances with proxy actors and leveraging asymmetric naval capabilities, Iran has effectively countered the Saudi–U.S. axis, safeguarded its strategic interests, and established a relative balance and deterrence in one of the world’s most geopolitically sensitive theaters—thereby advancing its national security