Iran Tankers Evade US Blockade with Crude

Source: bloomberg.com

TL;DR

The story at a glance

Two fully laden Iranian oil tankers, Hero II and Hedy, exited the Persian Gulf past a US blockade this week, according to satellite data from Vortexa. They joined a flotilla that has moved around US warships to deliver oil. This is being reported now after imagery confirmed their passage on April 20. The US imposed the blockade recently to restrict Iranian oil flows.[[1]](https://www.bloomberg.com/news/articles/2026-04-22/iran-tankers-go-dark-to-sail-past-us-blockade-laden-with-crude)[[2]](https://www.bloomberg.com/news/articles/2026-04-22/iran-tankers-go-dark-to-sail-past-us-blockade-laden-with-crude?srnd=homepage-americas)

Key points

Details and context

The US has stationed warships to enforce a blockade on vessels heading to or from Iranian ports, aiming to halt oil exports. Iranian tankers counter this by turning off their Automatic Identification System (AIS) transponders—known as "going dark"—and using satellite-blind routes or close coastal paths to slip past.

Vortexa, a data intelligence firm, tracked the Hero II and Hedy via satellite imagery after they passed the line on April 20, confirming they were loaded with crude. This follows a pattern where dozens of Iran-linked vessels have evaded similar restrictions, though US forces have intercepted and boarded some sanctioned tankers elsewhere.[[3]](https://www.wsj.com/livecoverage/iran-war-israel-us-strait-hormuz-2026/card/iran-dark-fleet-vessels-slip-through-blockade-FOA0FJA3PNxMk8IrHwAV)[[4]](https://apnews.com/article/iran-war-tifani-sanctioned-ship-bd0190ae22d133d85f331cb300b179bf)

The Strait of Hormuz remains a chokepoint, with normal tanker traffic down sharply since the blockade began around mid-April.[[3]](https://www.wsj.com/livecoverage/iran-war-israel-us-strait-hormuz-2026/card/iran-dark-fleet-vessels-slip-through-blockade-FOA0FJA3PNxMk8IrHwAV)

Key quotes

None.

Why it matters

Iran's ability to export oil despite the US naval presence challenges the blockade's effectiveness and sustains Tehran's revenue amid tensions. For oil markets, businesses, and investors, it means potential supply continuity but heightened risks of escalation or price swings from interdictions. Watch for more US interceptions, tanker movements via tracking firms like Vortexa, or official statements on blockade enforcement, though full success remains uncertain.

What changed

Omit.

FAQ

Q: What tankers passed the US blockade?

A: The Hero II and Hedy, two Iran-flagged very-large crude carriers, were captured by satellite moving past the US line into the Arabian Sea on April 20. They were fully laden and part of a flotilla evading warships. Vortexa provided the imagery and data.[[1]](https://www.bloomberg.com/news/articles/2026-04-22/iran-tankers-go-dark-to-sail-past-us-blockade-laden-with-crude)

Q: How much oil has the flotilla moved?

A: Roughly 9 million barrels of Iranian crude have reached the market. This includes loads from vessels like Hero II and Hedy that bypassed the blockade. The effort involved sailing around US warships.[[1]](https://www.bloomberg.com/news/articles/2026-04-22/iran-tankers-go-dark-to-sail-past-us-blockade-laden-with-crude)

Q: How do the tankers evade detection?

A: They "go dark" by switching off tracking transponders to sail past the US blockade undetected. Satellite imagery later confirms their positions and laden status. This tactic allows passage into areas like the Arabian Sea.[[1]](https://www.bloomberg.com/news/articles/2026-04-22/iran-tankers-go-dark-to-sail-past-us-blockade-laden-with-crude)

Q: What is the capacity of Hero II and Hedy?

A: The pair can carry as much as 4 million barrels of oil combined. They exited the Persian Gulf fully loaded per Vortexa data. This matches their classification as very-large crude carriers.[[1]](https://www.bloomberg.com/news/articles/2026-04-22/iran-tankers-go-dark-to-sail-past-us-blockade-laden-with-crude)