Hormuz Is Already Blocked — Is the Red Sea Next for Korea's Oil Supply?

South Korea's crude oil supply chain is now facing a two-chokepoint problem: the Strait of Hormuz has been effectively disrupted since the Iran conflict escalated earlier this year, and Yemen's Houthi movement has since declared a naval blockade against Saudi Arabia that threatens the Red Sea route Saudi exporters have been relying on as a workaround. Neither chokepoint has to fully close for Korean refiners to feel the effect — rerouted cargo simply becomes slower and more expensive to insure, and that cost eventually shows up in landed crude prices.

What Is Actually Happening in the Red Sea Right Now?

The backdrop is a chain of events that began earlier this year when the Iran conflict intensified, effectively taking the Strait of Hormuz — historically the route for roughly a fifth of the world's seaborne oil — out of reliable service. Saudi Arabia responded by shifting a large share of its exports onto its East-West pipeline system, sending crude overland to the Red Sea port of Yanbu and out through the Bab-el-Mandeb Strait instead. That workaround held for a while, until an airstrike on Yemen's Sana'a airport in mid-July — which Houthi officials blamed on Saudi Arabia while a Saudi-backed Yemeni government body claimed responsibility — prompted the Houthi movement to declare the informal truce with Riyadh over. On July 20, Houthi spokespeople announced a formal maritime blockade against "Saudi Arabia's enemies," paired with a general mobilization order. Layered on top of that, regional reporting has more recently pointed to growing cooperation between the Houthis and Sunni jihadist groups — Yemen's al-Qaeda affiliate AQAP and Somalia's al-Shabaab — that appears to be pushing military hardware further into the wider Gulf of Aden shipping corridor.

Why Does the Bab-el-Mandeb Strait Matter So Much for Global Oil Flows?

The Bab-el-Mandeb Strait, at the southern mouth of the Red Sea, narrows to roughly 29 kilometers at its tightest point — tighter even than the Strait of Hormuz. Regional shipping estimates put the volume of seaborne oil passing through it at somewhere around one-tenth of global trade in normal times, a share that has grown since Hormuz became unreliable and Saudi Arabia leaned harder on the Red Sea route. A strait that narrow does not require a conventional naval blockade to become dangerous — a relatively small number of drones or anti-ship missiles fired from the Yemeni coastline is enough to make commercial insurers and shipowners think twice about sending a tanker through.

A Red Sea blockade does not need to stop a single tanker to raise Korea's fuel bill — it only needs to make the detour around Africa look cheaper than the risk of sailing through Bab-el-Mandeb.

How Would This Actually Change the Route Korean Crude Tankers Take?

Since Hormuz became unreliable, Korean-bound VLCCs (very large crude carriers) loading at Yanbu have been running the Red Sea route — through Bab-el-Mandeb, up past the Horn of Africa, and on to Korea — a journey regional shipping sources estimate at roughly 6,500 nautical miles and about 20 days. If that route becomes too dangerous to insure, the fallback is the Cape of Good Hope: sailing around the entire African continent instead of through the Suez Canal system, a detour estimated at close to 15,000 nautical miles and roughly 50 days. Even sailing through the Suez Canal itself is not simple for a fully laden VLCC — a full cargo pushes a tanker's draft to around 22 meters, deeper than the Suez Canal's maximum permitted draft of about 20.1 meters, which means part of the cargo has to be pumped through the Sumed pipeline from Ain Sukhna to the Mediterranean and reloaded at Sidi Kerir before the ship can transit. None of this is a hard supply cutoff. It is a cost and time problem that compounds the longer the Houthi blockade threat stays credible.

Route (Saudi Red Sea Port to Korea)	Approx. Distance	Approx. Transit Time	Key Added Cost Factor
Via Bab-el-Mandeb & Suez system (current workaround)	~6,500 nautical miles	~20 days	War-risk insurance premiums reported to be climbing sharply since the blockade declaration
Via Cape of Good Hope (fallback if Red Sea is deemed unsafe)	~15,000 nautical miles	~50 days	Extra fuel and charter days; more tanker capacity tied up per delivered barrel
Direct Strait of Hormuz route (pre-disruption baseline)	Shortest of the three	Fastest of the three	Currently constrained by the wider Iran conflict, which is why the Red Sea workaround exists at all

What Does a Longer, Riskier Route Actually Cost?

Industry estimates cited in regional coverage of the standoff give some sense of scale, though exact figures move with the news cycle and should be treated as directional rather than precise. A single VLCC transiting the Suez Canal system with a partially lightered cargo reportedly incurs on the order of a million dollars in canal tolls and pipeline fees. Rerouting around the Cape of Good Hope instead adds a comparable amount in extra fuel and charter costs. On top of that, war-risk insurance on a Bab-el-Mandeb transit has reportedly been quoted as high as roughly 2.5% of a vessel's hull value in the days immediately following the blockade announcement — which, on a $100 million-class VLCC, works out to something in the neighborhood of $2.5 million in additional premium for a single voyage. None of these numbers are officially confirmed, and they are the kind of figures that can move quickly once underwriters get more clarity on how seriously the blockade is being enforced. But directionally, they explain why "the ship can still sail" is not the same thing as "the cost stays the same."

⚠️ This Is a Cost Problem, Not (Yet) a Supply Cutoff

Unlike Hormuz, the Red Sea has a real alternative in the Cape of Good Hope route — expensive and slow, but available. That matters because it caps the scenario at "materially higher landed cost and longer lead times" rather than "no oil arrives." It's also worth noting that responsibility for the Sana'a airport strike that triggered the blockade declaration is itself disputed — both Saudi Arabia and a Saudi-aligned Yemeni government body have been named as possible sources — which suggests an element of signaling and information warfare is mixed into this conflict alongside the physical risk. That ambiguity is a reason for caution before assuming the current trajectory toward escalation is locked in.

Why Is the Threat Profile Getting Worse Rather Than Better?

Two developments point toward the risk building rather than fading. First, the Houthis have reportedly issued a general mobilization order, and regional estimates — again, difficult to verify independently — suggest the movement's mobilizable manpower has grown substantially over the past few years as recruitment expanded beyond its original core of fighters. Second, and more specific to shipping risk in the wider Gulf of Aden, recent reporting describes a deepening arrangement between the Houthis and two Sunni jihadist groups that would ordinarily be their sectarian enemies: Yemen's AQAP and Somalia's al-Shabaab. The logic on both sides is transactional — al-Shabaab has built a substantial revenue base through taxation across Somalia (including, reportedly, in areas nominally controlled by the internationally recognized government) but has historically struggled to access weapons, while the Houthis have relatively cheap access to arms funneled in from Iran but need cash. Reports citing shipping and security sources describe attack drones already moving from Yemen into Somalia, missiles potentially following, and hundreds of al-Shabaab fighters reportedly receiving weapons training on Yemeni soil. Al-Shabaab's traditional area of operation sits directly along the Gulf of Aden approach to Bab-el-Mandeb, which is precisely the corridor Korean-bound tankers use.

✅ What to Track If You're Watching This Risk

• War-risk insurance quotes for Bab-el-Mandeb transits — a spike here tends to show up before shipowners actually start avoiding the route
• Reported export volumes moving through Saudi Arabia's Yanbu terminal, as a proxy for how much Middle East crude is still reaching Asia by the shorter path
• Whether Korean refiners (SK Energy, GS Caltex, S-Oil, HD Hyundai Oilbank) or their chartered carriers begin publicly rerouting cargo around the Cape of Good Hope
• Developments in Washington around the legal status of the renewed Iran conflict, since a US response tied to that dispute could also affect naval activity near both chokepoints

What Should Investors Watch Next?

The practical takeaway for anyone tracking Korea's energy exposure is that this is no longer a single-chokepoint story. With Hormuz already constrained, the Red Sea route was functioning as the pressure-release valve for Saudi and Emirati exports reaching Asia — and that valve is now the one under direct threat. For a deeper look at how the Hormuz disruption itself has been reshaping Korean refiners' sourcing and margins, see our related coverage on how the Strait of Hormuz closure is affecting Korean refiners, and for the broader picture of how Middle East supply shifts are filtering into Korea's crude sourcing strategy, see South Korea's crude oil sourcing shifts amid Middle East supply disruptions.

Frequently Asked Questions

Q1. Does a Red Sea blockade mean South Korea could run out of crude oil imports?

A. Not in the sense of oil becoming unavailable. The Cape of Good Hope offers a working, if far more expensive and slower, alternative to the Bab-el-Mandeb route. The realistic risk is higher landed crude costs and longer delivery lead times rather than an outright supply stoppage — unless the Red Sea disruption coincides with a simultaneous, sustained closure of the Strait of Hormuz, which would remove more of the available workarounds at once.

Q2. How much longer would a Korea-bound crude shipment take if tankers avoid the Red Sea?

A. Regional shipping estimates put the Yanbu-to-Korea run via Bab-el-Mandeb at around 20 days versus roughly 50 days via the Cape of Good Hope — a difference of about a month per voyage, which also ties up tanker capacity and can tighten availability across the wider VLCC fleet.

Q3. Which Korean companies are most exposed to this shipping risk?

A. Refiners that source heavily from the Middle East — SK Energy, GS Caltex, S-Oil, and HD Hyundai Oilbank — carry the direct exposure through crude procurement costs, while Korean shipping operators running VLCCs on Middle East-to-Asia routes face the insurance and scheduling side of the risk. Higher freight and war-risk premiums typically compress refining margins before they show up at the pump.

With Hormuz already constrained and the Red Sea's Bab-el-Mandeb Strait now under an active blockade threat, Korea's crude supply chain is running out of cheap detours — and every mile added to a tanker's route is a cost that eventually reaches the refining margin.