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Iran Conflict 2026
20APR

IRGC Navy writes its own Hormuz transit rulebook

3 min read
10:10UTC

Iran's Revolutionary Guard wrote its own transit rulebook for the Strait of Hormuz in the IRGC-aligned Farsi outlet Tabnak. The foreign ministry had no seat at the drafting.

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Key takeaway

Iran's Revolutionary Guard wrote the Hormuz transit rules itself, and its own foreign ministry's clearances no longer hold.

On 17 April the IRGC Navy (Islamic Revolutionary Guard Corps Navy, Iran's parallel naval force) published a formal four-condition order for the Strait of Hormuz in the IRGC-aligned Farsi outlet Tabnak 1. Non-military vessels may transit only by Iran-designated routes; military vessels are barred; every passage requires prior Guard Corps authorisation; the framework is tied to the Lebanon ceasefire holding.

The Tabnak publication lets Iran's military write over its diplomats in public. Two days later Foreign Minister Abbas Araghchi announced a civilian corridor opening, and the announcement lasted less than 24 hours. Despite the radio clearances Iran's own foreign ministry issued, the Guard Corps fired on the Indian-flagged Sanmar Herald and Jag Arnav on Saturday 18 April . A Sanmar Herald crew member was recorded on open channel saying Iran had cleared the vessel and was now firing on it anyway, which is the evidence the Tabnak order is load-bearing and the foreign ministry's clearances are not.

For shipowners routing hulls through the strait, the practical question is whose paper to obey. The rulebook the IRGC has now published is domestic Iranian doctrine with no signatory outside the Guard Corps. The 1968 Traffic Separation Scheme agreed between Iran, Oman and the IMO has governed Hormuz movement for 58 years, and Iran's own civilian foreign ministry is still a party to it. A counter-view from sympathetic commentators in Tehran is that the Tabnak order is a wartime clarification rather than a substitute for civilian law, and that a single ceasefire can fold it back. That reading is hard to sustain while the Guard Corps is firing on vessels the foreign ministry has cleared.

Deep Analysis

In plain English

Iran has two different armed forces: the regular military and the Islamic Revolutionary Guard Corps (IRGC), which is a separate, more ideologically driven force that reports to the Supreme Leader. On 17 April the IRGC Navy (its sea-going branch) published a set of four rules saying that no ship could cross the Strait of Hormuz without its personal permission, that military ships were banned entirely, and that the rules were tied to the Lebanon ceasefire holding. On 19 April Abbas Araghchi, Iran's Foreign Minister, separately announced the strait was open. Those two announcements directly contradict each other, and they came from two different parts of the same government. When Indian ships tried to follow the foreign minister's clearance, the IRGC fired on them anyway. The IRGC's written order, published two days earlier, turned out to be the one that governed the strait.

Deep Analysis
Root Causes

Iran never ratified the 1982 UN Convention on the Law of the Sea (UNCLOS), which grants transit passage rights through international straits. Tehran's domestic maritime law, updated in 2024, claims jurisdiction over 'hostile-linked vessels', a category broad enough to encompass any flag state that has sanctioned Iran.

The Tabnak four-condition order operationalises that domestic legal claim as a Guard Corps enforcement mechanism, creating a parallel legal architecture Iran can enforce without reference to international maritime law.

The IRGC Navy's institutional position since 2019 has been that Strait of Hormuz access is a tool of statecraft, not a neutral right. The Guard Corps has treated clearance authority as its own operational property through three rounds of tanker harassment. Araghchi's Friday corridor announcement conceded that institutional property without Guard Corps agreement, producing the split the Tabnak order makes legible.

What could happen next?
  • Precedent

    The Tabnak order establishes IRGC written doctrine as the operative transit framework, creating a model for future enforcement that bypasses Iran's civilian foreign policy machinery.

  • Risk

    Northwood planners drafting rules of engagement this week must write against a published adversary doctrine rather than a diplomatic silence, narrowing the range of enforceable coalition positions.

Sources:Tabnak
Mentions:Lebanon →IISS →Tanker War →Jag Arnav →India →Tehran →Gulf of Oman →Sanmar Herald →Oman →CENTCOM (US Central Command) →Khatam al-Anbiya Central Headquarters →IRGC Navy →Strait of Hormuz →Tabnak →USS Spruance →Touska →Islamic Revolutionary Guard Corps (IRGC) →Prima →Operation Praying Mantis →Abbas Araghchi →Iran →Truth Social →
First Reported In

Update #74 · Two unsigned rulebooks collide at Hormuz

Tabnak· 20 Apr 2026
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Causes and effects
Caused by
Hormuz opens then closes in 24 hours
The IRGC Navy's 17 April Tabnak transit order provided the written doctrine that retroactively explained the IRGC firing on Indian tankers that had radio clearance (ID:2578).
Occurred 17 Apr 2026
Read story →
This Event
IRGC Navy writes its own Hormuz transit rulebook
Iran now has a civilian enforcement track and a parallel military one, and the military one is the document tankers hit first in open water. A clearance from Iran's foreign ministry buys nothing the Guard Corps has not signed off.
Different Perspectives
Global South governments (Indonesia, Brazil, South Africa)
Global South governments (Indonesia, Brazil, South Africa)
Neutrality was possible when the targets were military. 148 dead schoolgirls made it impossible — no government can explain that away to its own citizens.
Trump administration
Trump administration
Oscillating between claiming diplomatic progress and threatening escalation, while deploying additional ground forces to the Gulf.
Israeli security establishment
Israeli security establishment
Fears a rapid, vague US-Iran agreement that freezes military operations before the IDF achieves what it considers full strategic objectives. A senior military official assessed the campaign is 'halfway there' and needs several more weeks.
Iraqi government
Iraqi government
Iraq's force majeure is the position of a non-belligerent whose entire petroleum economy has been paralysed by a war between others — storage full, exports blocked, production being cut with no timeline for resumption.
Russia — Ambassador Vassily Nebenzia
Russia — Ambassador Vassily Nebenzia
Moscow calibrated its position between Gulf states and Iran: abstaining on Resolution 2817 rather than vetoing it, signalling it would not block protection for Gulf states, while refusing to endorse a text that ignores the US-Israeli campaign it regards as the conflict's proximate cause. Russia proposed its own ceasefire text — which failed 4-2-9 — allowing Moscow to claim the peacemaker role while providing Iran with satellite targeting intelligence, a duality consistent with its approach in Syria.
France — President Macron
France — President Macron
France absorbed its first combat death in a conflict it has publicly declined to join. The killing of Chief Warrant Officer Frion in Erbil forces Macron to choose between escalating involvement and accepting casualties from the margins.