Why a U.S. blockade on Iran seems to be working

Key Points:

• The U.S. Navy has fully implemented a sea blockade against Iran, halting economic trade by sea and forcing Iran-linked or sanctioned vessels to stop, turn around, or jam their locations, according to U.S. Central Command and shipping data firms.
• The blockade is enforced impartially against all vessels entering or leaving Iranian ports, with U.S. forces intercepting ships in the Gulf of Oman beyond the Strait of Hormuz; no vessels have passed through in the first 48 hours.
• Some vessels, including previously sanctioned tankers like the Rich Starry, have attempted to evade detection by turning off transponders or spoofing locations, but many have complied by reversing course or halting movement.
• Iran has responded by threatening to block Gulf trade entirely if the U.S. blockade persists, warning it would cut off exports and imports across the Persian Gulf, Sea of Oman, and Red Sea, while continuing to vet and charge vessels passing through.
• The blockade includes provisions allowing humanitarian shipments to pass after inspection, but uncertainty remains for neutral ships and commercial traffic, contributing to a highly risky maritime environment amid ongoing geopolitical tensions.