The blockage of the Strait of Hormuz has forced authorities in Asia to confront questions about the security of other crucial shipping routes, including the Strait of Malacca, which is the world’s busiest waterway for international trade.
What is the Strait of Malacca?
The 900km Strait of Malacca, bounded by Indonesia, Thailand, Malaysia and Singapore, provides the shortest sea route from East Asia to the Middle East and Europe.
The route carries almost 22% of the world’s maritime trade, according to the Center for Strategic and International Studies. This includes oil and gas shipments from the Middle East to the economies of China, Japan and South Korea.
Malacca is the world’s largest “oil transit choke point” and the only one that surpasses Hormuz, according to the US Energy Information Administration.
In the first half of 2025, around 23.2 million barrels of oil per day were transported through the Strait of Malacca, representing 29% of total maritime oil flows. The second largest bottleneck, , had around 20.9 million barrels per day.
More than 102,500 vessels, mostly commercial ships, transited the Strait of Malacca in 2025, up from about 94,300 in 2024, data from the Malaysian Navy Department showed. This includes , but some very large ships avoid the strait due to depth restrictions and instead head south around Indonesia.
This route allows you to bypass the Strait of Malacca if it is closed, but it increases travel time, which would delay shipments and increase prices.
What are the concerns about the Strait of Malacca?
At its narrowest point in the Phillips Channel of the Singapore Strait, the Strait of Malacca is just 2.7 km wide, creating a natural chokepoint as well as the potential for collisions, grounding or oil spills.
Some parts of the strait are relatively shallow, with a depth of 25-27 meters, restricting larger ships, but even very large oil carriers (VLCCs) measuring over 350 meters long and 60 meters wide make the crossing.
For years, the strait was a hotbed of piracy and attacks on commercial ships. Last year, criminal attacks rose to at least 104, but declined in the first quarter of this year, according to the ReCAAP Information Sharing Center, an organization created by regional governments to combat piracy.
The narrow and congested waterway has been strategically important for Beijing, with about 75% of sea imports passing through there from the Middle East and Africa, according to data from tanker tracker Vortexa.
The Iran crisis has highlighted long-standing concerns about how chokepoints like Malacca could be affected if conflict erupts in the South China Sea or the Taiwan Strait, through which another 21% of global maritime trade transits, according to CSIS.
Malaysian authorities say the Strait of Malacca is also a growing location for illegal ship-to-ship transfers, where oil is transferred between tankers at sea to hide its origin.
What are the authorities saying?
Indonesian Finance Minister Purbaya Yudhi Sadewa caused controversy by openly reflecting on ways in which countries could impose tolls on ships as a way of monetizing the strait, before noting that this would not be possible.
When asked about the risks of tolls or other restrictions on movement across the strait, Singapore’s Foreign Minister Vivian Balakrishnan told CNBC that nations along the strait share a strategic interest in keeping it open and have agreed not to charge tolls.
He also said that Singapore has assured the United States and China that the right of passage is guaranteed to everyone and that it will not participate in any efforts to block the strait or impose tolls.
Malaysian Foreign Minister Mohamad Hasan told a forum that no unilateral decision can be made on the strait and that Malaysia is on the same page with Singapore, Indonesia and Thailand, which conduct joint patrols to ensure the waterway remains open.
