Houthi Saudi Blockade Drives Red Sea Tanker Transits to 11

On Sunday, 26 July 2026, just 11 commodity tankers crossed the Bab el-Mandeb Strait, the lowest daily count recorded in several months. The collapse followed a Houthi declaration, issued approximately 20 July, that all Saudi-bound shipping is now a legitimate military target. Within a week, two Saudi oil tankers were struck, missile and drone attacks hit Saudi Red Sea coast installations, and nearly a dozen vessels reversed course before reaching the strait.

The Houthi Red Sea attacks that began in late 2023 have entered a structurally different phase. What was an opportunistic campaign against Israel-linked vessels is now a formally declared blockade targeting a named sovereign state’s commercial fleet. This article breaks down what the vessel-tracking data recorded, how tanker operators are responding in real time, what the degradation of tracking visibility means for crude flow monitoring, and why diplomatic signals from Washington and Tehran have not moved a single ship back into the corridor.

Houthis escalate from opportunistic strikes to a declared Saudi blockade

The distinction matters. For more than two years, Houthi forces targeted commercial vessels with ties to Israel and its allies, a campaign that disrupted Red Sea shipping but left Saudi-flagged and Saudi-port-calling vessels largely outside the direct threat envelope. The blockade announcement of approximately 20 July 2026 changed that calculus entirely.

The escalation followed a clear sequence:

• ~20 July: Formal blockade declaration designating Saudi-port-calling vessels as military targets
• Week of 20-26 July: Two Saudi oil tankers struck
• ~25 July: Missile and drone attacks on Saudi oil installations along the Red Sea coast
• Post-announcement: Nearly a dozen vessels turned back before reaching Bab el-Mandeb, according to Kpler data cited by Reuters

Cyprus Mail reporting on tanker course reversals following the Houthi warning documented five vessels changing course in the Red Sea within days of the blockade declaration, a figure that aligns with the broader pattern of operator withdrawal now visible in Kpler’s daily transit counts.

The core distinction is structural: the Houthis have shifted from targeting vessel categories linked to Israel to imposing a formally declared blockade on a named country’s entire commercial shipping. This creates a different insurance, routing, and diplomatic calculus for every operator in the corridor.

What the vessel-tracking data actually recorded on 26 July

The headline figure is stark. Kpler vessel-tracking data recorded just 11 commodity tankers passing through Bab el-Mandeb on Sunday, 26 July, the lowest single-day count in several months. Seven of the 11 were oil tankers.

The composition of those flows tells its own story.

Even at these suppressed volumes, some barrels were still moving. The directional split, four outbound and three inbound, shows that neither loading nor delivery has fully halted. For traders modelling Saudi and UAE crude flows to Asia, the composition of what is still moving matters as much as the aggregate decline.

Traffic suppression extends to the Strait of Hormuz on 27 July

The suppression was not confined to a single chokepoint or a single day. Vessel traffic at both Bab el-Mandeb and the Strait of Hormuz remained at depressed levels on Monday, 27 July, according to Kpler data. This pattern points to operator-wide caution across the region rather than a localised, one-day reaction to the Sunday low.

Why Bab el-Mandeb matters to global oil supply chains

The Bab el-Mandeb Strait sits at the southern entrance to the Red Sea. Every barrel of crude, every container, and every LNG cargo moving between the Persian Gulf and Europe via the Suez Canal must pass through it. When that passage becomes too dangerous, vessels have one realistic alternative: the Cape of Good Hope.

Chokepoint closure and crude price formation have already been stress-tested in 2026: the effective shutdown of Hormuz drove Brent from roughly $70 to above $110 per barrel in under three months, with bypass pipeline alternatives unable to bridge the volume gap, a supply-side dynamic now replicating at a smaller but additive scale through Bab el-Mandeb.

The EIA chokepoint analysis for Bab el-Mandeb documented a significant decline in oil trade flows through the strait during 2024 as Houthi attacks accelerated, establishing a baseline against which the current suppression to 11 daily tankers represents a further structural deterioration.

Rerouting around the Cape of Good Hope adds approximately two weeks to a standard Persian Gulf to Europe voyage, based on standard industry calculations.

That time penalty translates into three compounding cost layers for operators and, ultimately, for buyers:

• Voyage time extension: Two additional weeks at sea per round trip, reducing effective fleet capacity
• Fuel and charter cost increase: Longer voyages consume more bunker fuel and tie up vessels that would otherwise be available for other cargoes
• War-risk insurance premium escalation: Insurers have repriced Red Sea transit risk upward as confirmed attacks have multiplied

The simultaneous suppression of traffic at both Bab el-Mandeb and the Strait of Hormuz on 27 July compresses the picture further. These are not independent chokepoints; when both are disrupted, the viable routing options for Middle Eastern crude to reach global markets narrow to a degree that affects the entire tanker system.

Tanker operators respond by going dark and reversing course

The aggregate numbers tell one story. The individual decisions being made aboard those tankers tell another.

At least one Saudi crude tanker was documented by Kpler transiting Bab el-Mandeb with its Automatic Identification System (AIS) transponder switched off, a system that broadcasts a vessel’s identity, position, speed, and heading in real time. Switching it off removes the vessel from the tracking screens that the Houthis, but also traders and analysts, rely on.

AIS dark operations at Hormuz followed a nearly identical pattern in early July 2026, when verified tanker crossings fell from a baseline of 80-100 per day to as low as five on some days and dozens of vessels went dark well above normal levels, a precedent that makes the Yanbu port-level deactivation documented here a logical next step in operator risk management.

Analysts at maritime intelligence firm Windward noted that “many vessels have switched off their location transponders to hide their positions from the Houthis.”

Operators are employing four distinct response types to the heightened threat:

• AIS-dark transit: Crossing the strait with transponders deactivated to avoid detection
• Course reversal: Vessels turning back near Bab el-Mandeb or in the Gulf of Aden
• Holding position: Ships anchoring and awaiting instructions from charterers or owners
• Suez diversion: Tankers that loaded at Yanbu heading north toward the Suez Canal rather than south through Bab el-Mandeb

Yanbu port operations shift entirely to AIS-dark at berth

Windward reports that Saudi Arabia’s Yanbu port, one of the country’s primary Red Sea crude export terminals, has shifted from predominantly AIS-active tanker operations to entirely AIS-dark at berth. This is not a vessel-by-vessel decision; it indicates a coordinated response to the targeting risk at the loading point itself.

The implication for supply chain transparency is direct. Loading activity at Yanbu is now effectively unmonitorable in real time, degrading the data that traders, cargo trackers, and inventory analysts depend on to model Saudi crude supply.

De-escalation signals from Washington and Tehran have not moved the market

Reuters reported “signs of de-escalation” between the United States and Iran as of Monday, 27 July. On the same day, vessel traffic at both Bab el-Mandeb and the Strait of Hormuz remained suppressed. Kpler data confirmed no traffic rebound.

The disconnect between political language and commercial behaviour is the unresolved tension at the centre of this story. Two categories of signal are telling contradictory stories:

• Diplomatic signals: US-Iran indications of short-term easing of hostilities, interpreted as tentative restraint
• Commercial signals: No return of vessels to the corridor, continued AIS deactivation, sustained suppressed daily transit counts

The market is effectively demanding a tangible and durable drop in actual attacks before shipowners resume normal routes, not diplomatic statements or ceasefire announcements.

Vessel operators have been through enough false signals since late 2023 to discount political language without supporting evidence. Shipper confidence is rebuilt by a sustained absence of attacks, not by the presence of statements.

Diplomatic signals failing to restore shipping confidence is not a new pattern: in late June 2026, Iranian drone strikes on two commercial vessels in Hormuz sent WTI up 2.56% even as Doha negotiations were 48 hours away, demonstrating that operators price demonstrated attack frequency rather than scheduled diplomacy.

What the opacity crisis means for crude flow visibility and energy markets

The corridor remains physically passable. Eleven tankers proved that on 26 July. But the market risk is no longer limited to whether ships can get through; it extends to whether anyone can see what is getting through.

Yanbu is entirely AIS-dark at berth. At least one confirmed AIS-dark transit was documented during the week. Outbound flows of Saudi, UAE, and Russian crude to China and Pakistan are still occurring, but with materially degraded real-time visibility. The information infrastructure that energy markets depend on, vessel tracking, cargo monitoring, inventory estimation, is being eroded alongside the physical transit volumes.

Three distinct risk categories are now compounding:

• Physical supply disruption: Record-low transits, course reversals, and a formally declared blockade reduce the volume of crude moving through the corridor
• Information opacity: Mass AIS deactivation and port-level dark operations degrade the ability to track what is moving, complicating supply forecasts and price formation
• Cost inflation: War-risk insurance premiums and Cape of Good Hope rerouting costs add to the effective delivered price of Middle Eastern crude

Insurance costs and rerouting economics add a third layer of market pressure

War-risk insurance premiums for vessels transiting or approaching the Red Sea have escalated alongside the security deterioration. Combined with the approximately two-week voyage extension for Cape of Good Hope rerouting, the financial pressure compounds for every barrel of Middle Eastern crude delivered to Asian buyers. The result is not just higher volatility in oil prices but a structurally harder-to-forecast market.

A crisis that was already severe just became structurally harder to resolve

The pattern is one of widening scope. Attacks began in late 2023 against Israel-linked shipping. By 20 July 2026, the Houthis had declared a formal blockade on Saudi commercial vessels. By 26 July, daily transits hit a multi-month low of 11 commodity tankers. The escalation has been neither sudden nor unpredictable, but each step has deepened the operational disruption.

What would recovery actually look like? Analysts and operators are watching for three conditions, in sequence:

1. A sustained drop in confirmed attack frequency, measured in weeks rather than days, demonstrating that the threat has materially diminished rather than paused
2. Return of AIS-active transits through Bab el-Mandeb, signalling that operators believe detection is no longer a targeting risk
3. Rising daily vessel counts at Bab el-Mandeb above the suppressed baseline of recent weeks, reflecting actual routing decisions rather than diplomatic optimism

The mass normalisation of AIS-dark transits through one of the world’s most critical chokepoints is itself a lasting change in maritime risk norms, one that is likely to persist even after attack frequency drops. The corridor’s transparency has been structurally degraded.

For investors wanting to model how long a chokepoint-driven supply disruption typically takes to unwind, our full explainer on the Hormuz supply normalisation timeline covers Saudi Aramco’s warning that recovery could extend into 2027, the IEA’s 400 million barrel emergency release and why it covered only four weeks of the deficit, and the Goldman Sachs and Bank of America rate-cut timeline shifts that followed.

Investors tracking this story through Kpler and Windward data will see the recovery in operator behaviour before it appears in diplomatic communiques. The ships will tell the truth before the statements do.

This article is for informational purposes only and should not be considered financial advice. Investors should conduct their own research and consult with financial professionals before making investment decisions.