Saudi Arabia’s Red Sea bypass is now running close to its operational ceiling just as Yemen’s Houthis signal they are back in the regional fight. That combination leaves a narrow margin for error at Bab el-Mandeb and raises a pointed question for the global economy: do the Houthis intend to put Red Sea trade back in their sights?

A bypass under strain

Riyadh has opened the taps on its main contingency route to work around the closure of the Strait of Hormuz, pushing its East-West pipeline system to roughly 7mn barrels per day (bpd), according to Bloomberg reporting on March 28. The headline figure has attracted most attention, but it describes pipeline capacity rather than what the Red Sea port system can actually clear onto tankers.

Bloomberg data cited by the Wall Street Journal indicate that Yanbu is currently loading about 5mn barrels per day of crude, with a further 700,000-900,000 bpd of refined products, while around 2mn bpd of pipeline throughput continues to serve refineries, power plants and desalination facilities on the Red Sea coast. Kpler estimates, again reported by the Journal, put effective crude loading capacity at closer to 4-4.5mn bpd, implying a structural gap of 500,000-1mn bpd between what can reach the Red Sea and what can leave on ships.

That mismatch is becoming visible. Kpler data cited by the Journal show more than 30 tankers waiting at anchor outside Yanbu, an unprecedented queue, with loading delays stretching to around five days during the current week. The same reporting distinguishes between a March month‑to‑date average of around 3.4mn bpd, recent weekly rates around 4.5mn bpd and individual days above 5mn bpd, underlining that the system has moved from ramp‑up to congestion rather than settling at a stable new plateau.

The pressures are not confined to crude. OPIS, citing Vortexa figures, has reported that Indian buyers are increasing liquefied petroleum gas liftings from Yanbu as an alternative to Hormuz routes, adding another product stream into the same port complex with no parallel outlet. What was designed as a contingency route is now carrying multiple cargo types at, or close to, capacity.

No more restraint

Further south, conditions at Bab el‑Mandeb have changed more subtly. On March 20, the Joint Maritime Information Center (JMIC) assessed the southern Red Sea and Bab el‑Mandeb as a “moderate” threat environment, noting that commercial traffic had returned to broadly historical patterns and that there had been no confirmed recent attacks or suspicious approaches. That assessment was premised on a period of Houthi restraint following the ceasefire in Gaza and a pause in maritime attacks.

That pause has now ended at the regional level, even if commercial shipping has yet to be hit. On March 28, Houthi forces launched missiles towards Israel, in what they presented as joining Iran and allied groups in the current phase of the conflict. The strike did not target merchant vessels, but it removed the assumption that the group would remain on the sidelines while other fronts escalated.

At the same time, the United States Maritime Administration has updated its formal guidance. Advisory 2026‑006 warns that, although the Houthis have not attacked commercial ships since the Israel–Gaza ceasefire in October 2025, they “continue to pose a threat to U.S. assets, including commercial vessels” in the Red Sea, Bab el‑Mandeb, Gulf of Aden, Arabian Sea and Somali Basin. The notice states that vessels with Israeli, US or UK links, or belonging to companies calling at Israeli ports, could face a heightened risk of hostile action and advises US‑flagged ships to consider switching off AIS transponders where safety permits.

In short, the corridor remains open, but it is no longer operating under the same assumptions that underpinned many bypass models only a week or two ago.

Proven force

The question for operators is not whether the Houthis could return to attacking shipping, but whether they judge it useful to do so. Since November 2023, the group has repeatedly demonstrated that it can threaten traffic through the southern Red Sea and Bab el‑Mandeb with a mix of missiles, one‑way attack drones and explosive surface craft.

Reuters has reported that, between late 2023 and mid‑2025, Houthi forces targeted more than 100 merchant ships, sinking two vessels, seizing another and killing at least four seafarers as part of a campaign they framed as support for Palestinians during the Gaza war. A subsequent factbox from ThePrint, also drawing on Reuters data, put the tally even higher, noting more than 100 ships targeted, four sunk and at least eight sailors killed. The pattern included both clearly Israel‑linked tonnage and vessels later found to have only tangential or historic connections.

During that period, the group effectively turned Bab el‑Mandeb into an episodic anti‑access zone, forcing many liners and tanker operators to reroute around the Cape of Good Hope at significant cost. While the intensity of attacks ebbed with the Gaza ceasefire and subsequent international strikes on Houthi launch sites, the technical capability has not disappeared.

Statement of intent

The weekend rhetoric from Sana’a suggests that maritime assets remain very much on the table. Mohammed Mansour, deputy information minister in the Houthi‑run administration, told Al‑Araby Television: “We are in joint coordination with our brothers in Iran, Lebanon, and Iraq.” He said the Houthis joined the conflict “to provide support to our brothers in Iran who are fighting epic battles” as well as the Lebanese group Hezbollah.

Mansour added that the group’s move “aims to increase pressure on Israel and the US,” stressing: “Every step we take is carefully calculated to be effective and to increase the pressure on Israel and the US.” Yemen, he argued, “bears a moral, religious, and humanitarian responsibility toward Iran, Hezbollah, and Iraq’s Popular Mobilization Forces,” describing the alliance as “primarily aiming to support Palestine.”

Crucially for shipowners, Mansour stated that the Houthis had “many options” to increase pressure and that “The Red Sea, the Gulf of Aden, and Bab al-Mandab will be among the options.” On whether they might close the strait or attack passing ships, he said: “This depends on the Israeli and US escalation, and the American preparations for any ground movement.” He emphasised that “The Yemeni leadership makes its decisions independently based on military and political assessments, taking into account that any step will be calculated and effective.”

Taken together, those remarks amount to a conditional but explicit threat to maritime traffic.

What next?

For now, the answer is that the Houthis have chosen to re‑enter the conflict by firing on Israel rather than by immediately resuming direct attacks on merchant ships. But their recent record, declared options and the evolving military context all point to a non‑trivial probability that shipping could again be targeted if they seek additional leverage.

Three factors bear watching. First, the nature and scale of any Israeli or US response to the latest strikes: Mansour has already linked potential action in the Red Sea and Bab el‑Mandeb to perceived escalation by those states. Second, the degree to which traffic through Yanbu and Bab el‑Mandeb continues to underpin global crude and LPG flows; as dependence on the bypass deepens, the strategic payoff from disrupting it increases. Third, the internal calculus in Sana’a about balancing regional signalling against the risk of renewed international strikes on Houthi assets.

The bypass is working, but it is doing so with queues at Yanbu, a crowded Red Sea and a security posture that now assumes a hostile group with both proven capability and openly stated interest in using the Red Sea, Gulf of Aden and Bab el‑Mandeb as pressure points. In that environment, it would be prudent to treat the absence of recent shipping attacks as a pause, not a guarantee.