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Executive summary
The Houthis announced a “ban” on Saudi Arabian ports effective July 20, 12:00 UTC, warning that vessels calling at Saudi terminals face sanctions and could be targeted anywhere within their operational reach. There is evidence of disruption with VLCCs and other vessels diverting to avoid transit through the Bab el Mandeb Strait, but too early to assess full impact.
Attacks have been claimed on vessels with Saudi Arabian-links. The current threat is perceived to be largely aimed at crude exports from Yanbu, which has become Saudi Arabia's critical relief valve during the Strait of Hormuz closure. Any strangulation of Saudi oil supplies via the Red Sea route will further weigh on energy shipments from the Middle East.
Key takeaways
Houthi ban on Saudi port traffic took effect July 20, 1200 UTC, with warnings of sanctions and targeting for non-compliant vessels.
Preliminary data from July 21 shows 33 transits through the Bab el Mandeb. 32 of these were traceable, one was dark. In terms of traceable transits, this figure is below the average daily number of transits for July (40), but it is well within the normal range for daily traffic, which fluctuates. Dark transit data is incomplete, and the figure will almost certainly be revised upwards in the coming days as more ships come back online.
Rerouting is already underway: at least three VLCCs bound for the Gulf of Aden U-turned or stopped by Tuesday (July 21) morning, a Cosco vehicle carrier reversed near Djibouti and two tankers that recently loaded at Yanbu altered course. One Chinese VLCC has been confirmed to have been granted safe passage by the Houthis, having previously U-turned following the blockade announcement.
Yanbu exports have surged roughly fivefold (763,229 bpd pre-crisis to 3.8m bpd) as the key alternative to Hormuz-constrained Gulf exports, driving up crude oil tanker transits that have been largely at par with pre-Houthi crisis levels (ie. prior to November 2023).
Transits through the Bab el Mandeb for the week ending ending July 19 were at their highest level since December 2023 as shipping — across sectors including tankers, bulkers and containerships — grew more confident in using the international passage. This trend is now at risk of reversing.
Risk appetite varies greatly across owners. Some have already diverted and changed routing plans, while others are waiting to see how the situation develops.
Tankers avoiding the southern Red Sea/Gulf of Aden means routing around Africa via Suez/SUMED — since a fully laden VLCC can't transit Suez, cargo must be partly offloaded at SUMED's Red Sea end and reloaded in the Mediterranean, adding time, fuel, and canal costs.
Source: Lloyd’s List Intelligence Red Sea Transit Monitor
Security summary
Threat is credible: maritime security agencies report Houthi missile and drone deployments around the Bab el Mandeb, and the Houthis have claimed two attacks on Saudi-flagged tankers as of the early hours of Thursday (July 23).
Saudi-owned fleets (e.g., Bahri, Aramco) are most likely immediate targets, but Houthis’ targeting criteria is broad and is based on trade patterns, which means vessels calling at Saudi ports or carrying Saudi cargo are exposed to risk regardless of ownership or flag.
About 23 Saudi-flagged vessels have disabled their AIS systems and are operating dark. While this behaviour predates the current escalation, it will likely become more commonplace.
Houthis’ can expand or alter the scope of their criteria and change the interpretation, putting foreign owners with recent Saudi port calls or trading history also at risk.
Operation Aspides rates overall Red Sea/Gulf of Aden threat as medium, but Saudi-, US-, and Israel-affiliated vessels as high risk, and recommends they avoid the area until tensions ease.
Owners are being advised to minimise AIS transmissions and limit publicly available voyage information to reduce targeting exposure.
Risk outlook
Bab el Mandeb traffic is likely to decline again if Houthi attacks resume in earnest, having just reached a post-crisis weekly peak.
Traffic volumes have never fully recovered to pre-Houthi crisis levels and have consistently been 40%-60% lower than normal levels, despite some shipping companies restarting Red Sea operations.
Risk tolerance is uneven across industry, and some owners and operators will continue to send ships through the Bab el Mandeb despite heightened tensions, as has been the case throughout the broader Red Sea crisis since 2023.
The main concern is impact to Yanbu exports as it’s Saudi Arabia’s principal workaround for the Hormuz closure. The structural alternative, routing via Suez/SUMED, is costlier and slower, and only partially substitutes for direct Yanbu lifting given VLCC draft/loading constraints through Suez.
Pressure on an already strained tanker market and global crude supply chain will be compounded by the Houthis’ blockade and any further attacks.
If you missed our latest Strait of Hormuz Crisis webinar briefing, featuring updates on the situation in the Red Sea, register and watch on demand here.
This briefing was complied by the Maritime Intelligence Unit
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