Transit or no transit – that’s the question in International Shipping News 27/04/2026 Since 13 April, the challenge for vessels to enter or leave the Middle East Gulf has been complicated significantly. While in the first 1.5 months of the conflict the full focus was on the Strait of Hormuz, the targeted US blockade on Iranian or Iran-related vessels is geographically much less specific. Accordingly, we have to differentiate two distinct and operationally independent blockades: • Iranian de facto closure of the Strait of Hormuz enforced by the IRGC since 28 February, • A US naval blockade of Iranian ports initiated by CENTCOM on 13 April, which is not necessarily implemented close to Iranian ports nor within the Strait of Hormuz, but flexibly around an area about 300miles to the West between the Pakistani/Iranian border and the most eastern “corner” of Oman. These two instruments target different actors, operate under different legal frameworks, and have different geographic reach. And there is no linkage between the passage of the two blockades. In fact, individual vessels will likely face challenges either • with the passage of the Strait of Hormuz (non-Iranian vessels or no agreement with Iran – in that case the US blockade is unlikely to apply) • Or with the US blockade (for Iranian vessels or vessels with close ties/agreements with the Iranian side – in that case the Strait of Hormuz is unlikely to be the challenge) Understanding this distinction is now the single most important analytical lens for tracking flows, Gulf export disruption, and the prospects for physical market recovery. Map shows passages through the US blockade (updated April 20) Vortexa has observed the following on the water activity for energy tankers related to the US Naval Blockade, focussing solely on sanctioned tankers and those with Iranian links (loaded from Iranian ports currently or in recent months) (all other tankers from the eastern part of the UAE or Oman are supposedly free to pass). → 34 energy tankers with Iranian links transited the area (inbound and outbound) (April 13 – April 21) → 6 dark outbound transits were carrying 10.7mn barrels of Iranian crude (April 13 – April 21), as of April 22, 3 have reportedly been interdicted by the US → All crude carriers have transited with AIS disabled Passages via the Strait of Hormuz In parallel to the US naval blockade, passages through the Strait of Hormuz have not collapsed outright, but have instead shifted into a more selectively constrained transit environment. On average, 4.5 transits per day were observed between April 13-21, compared to 4 transits per day in the preceding 30 days – indicating that baseline throughput has been broadly maintained, despite heightened tensions. However, since the introduction of the US blockade, Iran-linked activity has declined with 1-2 tankers per day transiting the Strait of Hormuz between April 13-21, compared to 2-3 per day in the preceding 30 day period. Recent events suggest that enforcement has become more kinetic and selective, with Iran targeting vessels attempting to exit the Strait without alignment or authorization. Importantly, this dynamic is not universally applied: → Non-Iranian vessels without agreement are increasingly challenged at the Strait → Iranian-linked vessels, by contrast are more likely to face risk further downstream within the US blockade environment, not at the Strait of Hormuz Impact on Iranian crude production, storage and flows While ca