Maritime Chokepoints Explained: The Eight Sea Routes Island Economies Depend On
A maritime chokepoint is a narrow passage on a busy sea route where a closure, attack or drought can delay a large share of world trade at once. The U.S. Energy Information Administration tracks seven oil chokepoints plus the Cape of Good Hope; in the first half of 2025 the Strait of Malacca carried about 23.2 million barrels of oil a day and the Strait of Hormuz about 20.9 million. Islands sit at the far end of these routes, so they feel the delay and the price rise without having any control over the cause. In 2026, the Middle East conflict’s disruption of fuel supply chains led Pacific Islands Forum leaders to invoke the Biketawa Declaration. The practical lesson is to know which chokepoints your fuel, food and medicine pass through, and to hold enough stock to cover a reroute.
What a maritime chokepoint is
The U.S. Energy Information Administration (EIA) defines chokepoints as narrow channels along widely used global sea routes that are critical to energy trade because of the volumes that pass through them. Blocking one, even briefly, can cause supply delays, higher shipping costs and higher energy prices. Most can be bypassed by longer routes, but some have no practical alternative (EIA). For an island, a chokepoint thousands of miles away can decide how long the fuel at its one port will last.
Most of the world’s oil moves by sea. EIA estimates that in the first half of 2025 about 76 percent of world oil supply, or 79.8 million barrels a day, traveled by seaborne trade (EIA). Container goods, grain, fertilizer and liquefied natural gas use many of the same lanes. When one of those lanes narrows to a strait or a canal, every ship on the route has to pass the same point.
Two things make a chokepoint matter: how much passes through it and how hard it is to go around. EIA ranks Hormuz and Malacca first by oil volume (EIA). UNCTAD adds that Hormuz handles about 11 percent of global maritime trade by weight, including about 34 percent of seaborne oil exports and 30 percent of liquefied petroleum gas exports (UNCTAD Review of Maritime Transport 2025). The Cape of Good Hope is not a chokepoint, but EIA tracks it because it is the main detour when the Red Sea route is unsafe (EIA).
ISPI’s interest is the island end of the route. A large economy can draw down reserves, switch suppliers or move cargo overland. A small island usually has one port, a few weeks of fuel and no overland option, the condition ISPI calls supply chain singularity. A disruption that adds two weeks to a voyage elsewhere can mean an empty fuel terminal on an island. This explainer is part of ISPI’s ports and maritime security research hub and its supply chain and infrastructure hub.
The eight routes at a glance
The table uses EIA’s most recent chokepoint report, last updated March 3, 2026, which covers data through the first half of 2025 (EIA). It does not yet reflect the 2026 disruption at Hormuz described below.
| Route | What it connects | 2024 | First half of 2025 | Main alternative named by EIA |
|---|---|---|---|---|
| Strait of Malacca | Indian Ocean and Pacific Ocean | 22.5 | 23.2 | Sunda and Lombok straits in Indonesia, or the long route around the archipelago; the Myanmar–China crude pipeline |
| Strait of Hormuz | Persian Gulf and Gulf of Oman / Arabian Sea | 20.7 | 20.9 | Saudi East-West and UAE Abu Dhabi pipelines, about 4.7 combined; Iran’s Goreh-Jask pipeline, about 0.3 |
| Suez Canal and SUMED pipeline | Red Sea and Mediterranean | 4.8 | 4.9 | Cape of Good Hope |
| Bab el-Mandeb | Red Sea and Gulf of Aden / Arabian Sea | 4.1 | 4.2 | Cape of Good Hope |
| Danish Straits | Baltic Sea and North Sea | 4.9 | 4.9 | Kiel Canal (small tankers, about 0.2) |
| Turkish Straits (Dardanelles figure) | Black Sea, Sea of Marmara and the Mediterranean | 3.6 | 3.7 | Baku-Tbilisi-Ceyhan and Iraq–Türkiye pipelines |
| Panama Canal (fiscal years) | Pacific Ocean and Caribbean / Atlantic | 2.0 | 2.3 (FY2025) | Strait of Magellan, Cape Horn or Drake Passage; Trans-Panama Pipeline |
| Cape of Good Hope (not a chokepoint) | Indian Ocean and Atlantic Ocean | 9.3 | 9.1 | It is itself the main detour for Suez and Bab el-Mandeb traffic |
Two patterns stand out. First, Asia is the destination for most of the oil passing the two largest chokepoints: EIA estimates that 89 percent of the crude and condensate moving through Hormuz went to Asian markets in the first half of 2025, and China alone accounted for 48 percent of import volumes passing Malacca (EIA). Second, the Red Sea route had already shrunk before 2026. Flows through Suez and SUMED, and through Bab el-Mandeb, were about half their 2023 level, while flows around the Cape rose by 3 million barrels a day from 2022 (EIA).
Each chokepoint in brief
Strait of Malacca and the Singapore Strait
Malacca is the shortest sea route between Middle East suppliers and East and Southeast Asia, and the largest oil chokepoint in the world, carrying about 29 percent of maritime oil flows in the first half of 2025 (EIA). EIA notes that piracy and armed robbery against ships there increased after 2023, especially around Singapore. Indonesia, Malaysia and Singapore co-manage the straits through a Cooperative Mechanism that brings governments and industry together to share the cost of navigation safety, which the IMO Council highlighted in July 2026 (IMO Council, July 2026).
Strait of Hormuz
Hormuz, between Oman and Iran, links the Persian Gulf to the Gulf of Oman. EIA describes it as deep and wide enough for the largest crude tankers, with alternatives that could move only part of the volume if it closed (EIA). The International Energy Agency puts 2025 flows at about 20 million barrels a day, around a quarter of seaborne oil trade, and notes that Qatar and the UAE ship almost all of their liquefied natural gas exports through the strait (IEA).
Suez Canal, SUMED pipeline and Bab el-Mandeb
These three form the Red Sea route between the Indian Ocean and Europe. The SUMED pipeline across Egypt can carry 2.5 million barrels a day. After attacks on commercial ships in the Red Sea began in November 2023, many vessels switched to the Cape of Good Hope. EIA estimates that closing Suez and SUMED would add about 15 days to a tanker voyage from the Arabian Sea to Europe (EIA). UNCTAD reports that the Cape detour added about 30 percent to voyage lengths on the East Asia–Europe container trade (UNCTAD Review of Maritime Transport 2025).
Danish Straits
The Danish Straits connect the Baltic and North seas. EIA estimates about 4.9 million barrels a day passed in the first half of 2025, almost 60 percent more than in 2021, because trade flows shifted after 2022 (EIA). Seabed cables and pipelines share many of the same busy lanes, a risk ISPI covers in its undersea cables explainer.
Turkish Straits
The Bosporus and the Dardanelles connect the Black Sea to the Mediterranean through Türkiye. Less than half a nautical mile wide at the narrowest point, they are among the hardest waterways in the world to navigate, and more than 45,000 vessels passed through them in 2024. Türkiye does not allow liquefied natural gas cargoes through the Bosporus for safety reasons (EIA).
Panama Canal
The canal links the Pacific with the Caribbean and Atlantic. EIA notes that it matters most for refined products and liquefied gas, which travel on smaller ships, and that water shortages at Gatún Lake cut flows during the 2023–24 drought (EIA). It is the one chokepoint on this list where the main threat is climate rather than conflict.
Cape of Good Hope
The Cape is the pressure valve. EIA estimates that about 9.1 million barrels a day, 11 percent of seaborne oil, went around it in the first half of 2025, with Red Sea disruptions keeping flows above historical averages (EIA). A detour around the Cape is safer, but it takes longer and burns more fuel, and those costs are passed on to everyone at the end of the route.
What 2026 has shown
Three chokepoints have been tested this year, and each shows a different kind of failure.
Hormuz: conflict. According to the IMO, a conflict in the Middle East began on Feb. 28, 2026. By Sept. 16, the IMO had verified 80 attacks on international shipping in and around the Strait of Hormuz, with at least 22 seafarers killed. The IMO Secretary-General said the attacks are not attributable to a single actor (IMO, Sept. 16, 2026). In late August, the IMO reported that up to 400 ships carrying around 6,000 seafarers had been unable to leave the Persian Gulf safely since the conflict began (IMO, Aug. 28, 2026). In July, the IMO Council condemned attacks on civilian commercial ships in and around the strait. In a resolution, it stressed that the right of transit passage through straits used for international navigation should not be impeded or suspended, and it reaffirmed that passage should remain free of tolls and charges (IMO Council, July 2026).Red Sea and Gulf of Aden: renewed attacks and piracy. The IMO condemned renewed attacks on shipping in the Red Sea in July (IMO, July 23, 2026), and in August it reported seafarer deaths after the cargo ship TIHAMAH was hit by a projectile off Al Mokha, Yemen (IMO, Aug. 12, 2026). In October, the IMO reported that 44 seafarers had been freed from three vessels hijacked between April and August 2026 in the Western Indian Ocean and Gulf of Aden region, and that five crew members reportedly died during the rescue of one of them (IMO, Oct. 2, 2026).Panama: water. The Panama Canal Authority reported 13,951 transits in fiscal year 2026 (October 2025 to September 2026), up 4.1 percent (Panama Canal Authority, Oct. 21, 2026). Even so, on Sept. 28 it set the maximum draft in the Neopanamax locks at 49.0 feet and said a water deficit continues in the canal watershed, so a booking remains the only way to guarantee a transit date (Panama Canal Authority, Sept. 28, 2026).For the Pacific, the Hormuz disruption became a regional crisis. On May 8, 2026, Pacific Islands Forum Leaders invoked the Biketawa Declaration to coordinate a response to the energy crisis, as the conflict continued to disrupt fuel supply chains, and the heads of the regional organizations set up a CROP Taskforce on the Middle East Crisis (Pacific Islands Forum Secretariat, May 8, 2026). Two weeks later, Forum Foreign Ministers noted that members remain vulnerable through dependence on imported fuel and concentrated maritime supply chains. They supported a regional fuel security audit, noted the importance of stronger fuel storage arrangements onshore and offshore, and discussed collective engagement with major fuel suppliers such as Singapore (Special Forum Foreign Ministers Meeting outcomes, May 22, 2026). ISPI’s analysis of the Forum’s Biketawa invocation over fuel and our analysis of the Philippines’ March 2026 energy emergency cover those events in more detail.
Why chokepoints are an island problem
Island governments do not control any of the eight routes, but they absorb the consequences. UNCTAD’s 2025 review says persistent rerouting has increased exposure to delays and rising costs, especially for least developed countries and small island developing States, and that small island developing States are watching their import bills rise (UNCTAD Review of Maritime Transport 2025). It also reports that seaborne trade measured in ton-miles grew 5.9 percent in 2024, close to three times the growth in trade volume, because ships were sailing longer routes (UNCTAD Review of Maritime Transport 2025).
Four features of island economies turn a distant chokepoint into a local emergency:
- Fuel runs everything. On many islands, imported diesel and other fuels run power plants, water pumps, desalination, hospitals, fishing fleets and interisland ferries.
- Stocks are small. Storage tanks are sized for routine resupply, not for a reroute that adds weeks. Forum Foreign Ministers noted the importance of stronger fuel storage arrangements for this reason.
- Islands sit at the end of the line. Products often reach small islands by transshipment through regional hubs, so a delay upstream compounds at every handoff.
- Prices pass straight through. Higher freight and insurance costs on a rerouted voyage reach the final island price, often with no domestic alternative to switch to.
- IMO statements and press briefings for verified attack counts and the international legal position (IMO, Sept. 16, 2026).
- UKMTO (United Kingdom Maritime Trade Operations) for security alerts in the Middle East and Indian Ocean reporting area.
- Panama Canal Authority advisories to shipping for draft limits and booking rules (Panama Canal Authority, Sept. 28, 2026).
- IMF PortWatch, the open platform developed by the IMF with the University of Oxford that tracks port calls and chokepoint transits from ship-tracking (AIS) data.
- EIA and the IEA for oil flow volumes, and UNCTAD’s annual review for freight and trade effects (UNCTAD Review of Maritime Transport 2025).
- Map the route, not just the supplier. For fuel, food staples and medicines, record where each shipment originates, which hub it passes through and which chokepoints sit on the way. A refined-fuel supplier in Asia may still depend on crude that crossed Hormuz.
- Convert delay into days of stock. If a Cape diversion adds about 15 days to a tanker voyage from the Arabian Sea to Europe, ask what a comparable delay would do to your own resupply cycle, and set minimum stock levels to cover it.
- Treat storage as security infrastructure. Forum Foreign Ministers stressed fuel storage, onshore and offshore, in 2026. Storage also brings its own risks, as ISPI’s Red Hill explainer on fuel and drinking water shows.
- Use regional mechanisms early. The Biketawa invocation, the CROP taskforce and the regional fuel security audit exist so small members do not have to negotiate alone.
- Write a supply-shock annex into continuity plans. Decide in advance which services get fuel first if stocks fall: power, water, hospitals, communications and emergency transport.
- Exercise it. Run a tabletop that starts with a chokepoint closure and ends at the island fuel terminal, with the energy office, port, customs, suppliers and emergency management at the same table.
- U.S. Energy Information Administration, World Oil Transit Chokepoints (last updated March 3, 2026)
- International Energy Agency, Strait of Hormuz (oil security page)
- UNCTAD, Review of Maritime Transport 2025: Staying the course in turbulent waters (PDF)
- International Maritime Organization, Stop attacking merchant ships and seafarers: IMO Secretary-General to Member States, September 16, 2026
- International Maritime Organization, Six months of uncertainty for seafarers in Strait of Hormuz, August 28, 2026
- International Maritime Organization, IMO Council reaffirms commitment to protecting vital shipping lanes, July 13, 2026
- International Maritime Organization, Statement on recent attacks on ships in the Red Sea, July 23, 2026
- International Maritime Organization, Statement on deadly ship attack in the Red Sea, August 12, 2026
- International Maritime Organization, IMO Secretary-General mourns seafarers killed during rescue of hijacked ship, October 2, 2026
- Panama Canal Authority, Panama Canal Reports Growth in Transits and Tonnage in Fiscal Year 2026, October 21, 2026
- Panama Canal Authority, Panama Canal announces increase in draft and daily transit, September 28, 2026
- Pacific Islands Forum Secretariat, Forum Leaders Invoke Biketawa Declaration, May 8, 2026
- Pacific Islands Forum Secretariat, 2026 Special Forum Foreign Ministers Meeting: Outcomes, May 22, 2026 (PDF)
- United Nations, Convention on the Law of the Sea, Part III, Articles 37–44 (PDF)
- United Kingdom Maritime Trade Operations (UKMTO)
- IMF PortWatch
Hawaiʻi shows the same pattern at state scale. ISPI’s explainer on Honolulu Harbor and the single-port state describes how almost everything the islands import arrives through a few harbors. Australia and New Zealand face their own version of the question, covered in our review of ANZAC 2035 and Pacific energy security.
The legal rules for passage, in brief
Most of the straits on this list are straits used for international navigation. Under Part III of the UN Convention on the Law of the Sea, all ships and aircraft in such straits enjoy the right of transit passage, which shall not be impeded, and States bordering the strait shall not hamper transit passage and shall not suspend it (UNCLOS, Part III). Canals such as Suez and Panama are artificial waterways run under their own laws, treaties and operating rules.
In July 2026, the IMO Council restated those principles for Hormuz. It said any arrangement between the littoral States should guarantee non-discriminatory passage of all ships through the traffic separation scheme the IMO adopted in 1968, and asked the Secretary-General to work toward a coordinated and sustainable return to unhindered navigation (IMO Council, July 2026). ISPI reports the positions of international bodies and governments as published and does not take sides in the underlying conflict. The Island Security Agreements Tracker lists UNCLOS and the main regional maritime security instruments with official sources.
How to follow chokepoint risk without a subscription
Island agencies rarely have analysts dedicated to shipping. These free, official sources cover most of what a fuel or emergency manager needs:
Set a simple trigger: if a chokepoint on your supply route moves to elevated risk, check fuel stocks, call suppliers about delivery dates and brief the emergency management agency that week.
What this means for island and coastal governments
Chokepoints are not something an island government can fix, but it can decide how exposed it is when one closes. Six steps follow from the evidence above:
These steps connect to the rest of ISPI’s work: the continuity of operations guide for island local government, our Red Hill explainer, the Biketawa Declaration explainer, WP-06 on island supply chain security and the Cyber Continuity Checklist, which includes a maritime annex for port teams.
Frequently asked questions
What is a maritime chokepoint?
A narrow channel on a widely used sea route, such as a strait or canal, where large volumes of oil, gas and other cargo pass. Blocking it, even briefly, can delay supplies and raise shipping costs and energy prices.
Which chokepoint carries the most oil?
The Strait of Malacca. EIA estimates it carried about 23.2 million barrels a day in the first half of 2025, about 29 percent of maritime oil flows. The Strait of Hormuz was second at about 20.9 million barrels a day.
Is the Cape of Good Hope a chokepoint?
No. EIA tracks it because it is the main alternative route when the Red Sea route through Bab el-Mandeb and Suez is unsafe. EIA estimates closing Suez and SUMED would add about 15 days to a tanker voyage from the Arabian Sea to Europe.
How has the 2026 Hormuz crisis affected Pacific islands?
Pacific Islands Forum Leaders invoked the Biketawa Declaration on May 8, 2026 to coordinate a regional response to the energy crisis. Forum Foreign Ministers later supported a regional fuel security audit and noted the importance of fuel storage and engagement with major suppliers such as Singapore.
What is transit passage?
A right under Part III of the UN Convention on the Law of the Sea. Ships and aircraft may pass through straits used for international navigation continuously and expeditiously, and States bordering the strait may not hamper or suspend that passage.
ISPI publishes its research free under CC BY 4.0. If your government, agency or organization needs a fuel and supply route exposure assessment, a chokepoint disruption tabletop exercise, or a briefing on maritime security for island ports, you can commission research from ISPI. ISPI is a nonprofit organization; its application for 501(c)(3) tax-exempt status is pending. Contributions are not tax-deductible until IRS recognition is granted.
