Three Iranian tankers—the VLCCs Diona and Hero 2, and the Suezmax-class Sonia I—have crossed the perimeter of the American naval blockade in the Gulf of Oman, carrying a combined 4.8 million barrels of crude oil. Maritime tracking data confirmed the movements late on Tuesday, marking the first Iranian crude exports since the United States imposed the blockade on 13 April. The vessels are now heading east towards Asian markets, with the Sonia I reportedly bound for Singapore.

The breakthrough comes just days after Washington and Tehran announced a preliminary framework agreement, with a formal memorandum of understanding due to be signed in Switzerland on Friday. President Trump declared on social media that he had authorised the “free reopening of the Strait of Hormuz” and the immediate removal of the naval blockade. Viewed from Washington, the move is a calculated de-escalation after weeks of heightened military tension, but officials have cautioned that the deal remains provisional; Trump himself warned that if the final terms prove unsatisfactory, the United States would resume bombing. The memorandum, reportedly containing 14 points, allows Iran to resume oil sales immediately, though its full text has not been published.

In Tehran, the resumption of exports is being framed as a hard-won concession. The blockade had severed the Islamic Republic’s most vital economic artery, and the sight of National Iranian Tanker Company vessels sailing freely again is a tangible boost for a government under severe fiscal strain. Analysts in London, however, note that the framework is fragile. The two sides have committed to negotiating a comprehensive peace agreement within 60 days, a tight window that leaves ample room for brinkmanship and domestic opposition in both countries. The tanker movements serve as a confidence-building measure, but the deeper disputes—from Iran’s nuclear ambitions to its network of regional proxies—remain unresolved.

Asian energy markets are absorbing the development with cautious interest. China, the largest buyer of Iranian crude, has seen lacklustre refining margins, which may limit the immediate appetite for new cargoes. Global oil prices have edged lower, with Brent dipping below $80 a barrel, though analysts in Singapore say the market is still pricing in considerable uncertainty over the durability of the diplomatic track. The reactivation of the shipping corridor is nonetheless a logistical milestone; a fourth, empty tanker was observed heading into the Gulf of Oman, suggesting that the full export chain is being restored.

Friday’s signing ceremony will be scrutinised for any signal of the deal’s longevity. If the memorandum holds, it could open a pathway to a broader Middle East settlement, but the road is littered with potential spoilers—hardliners in both capitals, the complex architecture of sanctions that would need to be unwound, and the ever-present risk of miscalculation in the crowded waters of the Strait of Hormuz. For now, the passage of these tankers is a concrete indication that diplomacy, however tentative, is translating into barrels on the water.