KUALA /SINGAPORE, May 7 (Xinhua) — In the historic Malaysian city of Malacca, a long stone stele bears an inscription in English, Malay, Chinese and Arabic: “The Longest and Busiest Strait in the World.” This waterway, lying between the Malay Peninsula and the island of Sumatra, serves as a “maritime crossroads” connecting the Indian Ocean and the Pacific Ocean.
The Strait of Malacca is not only a vital passage for energy resources such as oil entering Asia but is also deeply embedded in the global supply chain, functioning as a crucial corridor supporting regional and even global trade. The conflict in Iran has disrupted passage through the Strait of Hormuz, transmitting shipping pressures outward. Against this backdrop, the strategic sensitivity of the Strait of Malacca has significantly increased, putting pressure on littoral states in areas such as transit efficiency, port transshipment, navigational safety, and strait governance.
Risk One: Pressure on Transit Efficiency and Port Operations
The Strait of Malacca stretches over 900 kilometers, connecting the Andaman Sea to the west and the South China Sea to the east. Its widest point in the northwest is about 250 kilometers, while its narrowest point in the southeast is only about 38 kilometers, giving it a funnel-like shape. According to data from the U.S. Energy Information Administration, approximately 20 to 25 percent of global maritime trade and about 25 percent of seaborne oil passes through the Strait of Malacca. Reports indicate that nearly 100,000 vessels transited the strait in 2025, keeping it in a state of high operational load for an extended period. Currently, the primary risks facing the Strait of Malacca are issues related to safety order and transit efficiency associated with high shipping density.
Pan Jinming, Director of the Institute of Internationalization and ASEAN Studies at the International Islamic University Malaysia, believes that within the global energy supply chain, the Strait of Hormuz and the Strait of Malacca serve as sequential nodes, jointly supporting the cross-regional flow of energy from production areas to consumer markets. Should the Strait of Hormuz remain closed for an extended period, the Strait of Malacca, already handling high-density shipping, will face additional spillover pressures from energy reallocation, schedule rescheduling, and regional transshipment.
The disruption of passage through the Strait of Hormuz leads to adjustments in global shipping routes, temporarily suppressing traffic volume through the Strait of Malacca. Once shipping in the Middle East returns to normal, the concentrated release of delayed and rescheduled transport demand will create a phenomenon of initial obstruction followed by concentrated port arrivals, increasing anticipated pressure on the Strait of Malacca’s shipping lanes.
The shallowest depth of the Strait of Malacca is approximately 25 meters, with numerous shoals in some areas, limiting the deep-water channels available for large ships and container vessels. Risk management service provider Helix International stated that as traffic flow is released intensively and shipping frequency becomes increasingly dense, the risk of congestion in the Strait of Malacca exhibits cumulative characteristics. Once a critical threshold is breached, it could lead to systemic collapse.
Jiajiameng Bidatunlongji, Director of the Centre for Multilateralism Studies at the S. Rajaratnam School of International Studies, Nanyang Technological University, Singapore, pointed out that increased shipping density will significantly raise the risk of accidents. In the event of a collision, it could not only delay or even interrupt shipping but also lead to environmental pollution and other issues.
Furthermore, pressure is also evident at the port level along the Strait of Malacca. Taking Malaysia’s Port Klang as an example, an increase in inbound cargo volume coupled with slower outbound processing has led to cargo backlogs and extended vessel waiting times, further impacting waterway transit efficiency. In response, littoral states like Malaysia have shifted from routine management to preventive deployment. Since March, relevant Malaysian government departments, addressing maritime disruptions caused by the Middle East conflict, have implemented measures such as clearing empty containers from port areas, strengthening unloading inspections, and optimizing port scheduling to prevent cargo accumulation from increasing congestion risks.
Risk Two: Security Hazards in Strait Transit
The Strait of Malacca has long been a high-risk area for pirate activities. Entering the 21st century, this threat has diminished but not been eliminated. The region remains one of the most concentrated areas for maritime security incidents in Asia and globally. Data from the Information Sharing Centre of the Regional Cooperation Agreement on Combating Piracy and Armed Robbery against Ships in Asia shows that in 2025, a total of 108 incidents of piracy and armed robbery against ships occurred in the Strait of Malacca, accounting for 82 percent of all incidents in Asian waters.
To ensure the strait’s security, littoral states of the Strait of Malacca have conducted joint patrols and shared intelligence since 2004. Between 2005 and 2007, the littoral states and the International Maritime Organization held annual meetings, establishing three cooperation mechanisms: the Forum for Technical Experts on Maritime Security Cooperation, the Project Coordination Committee, and the Navigation Assistance Fund, to ensure the safety of vessel navigation.
As the impact of the Iran conflict continues to spill over, littoral states are persistently strengthening coordinated control. On April 17, Indonesia, Malaysia, and Singapore reaffirmed their commitment to ensuring the Strait of Malacca remains open and safe for navigation in accordance with international law. On April 22, Malaysian Foreign Minister Mohamad Hasan stated at a forum that no single country can make decisions regarding any matter concerning the Strait of Malacca. Littoral states will ensure transit safety through mechanisms such as joint patrols.
Malaysian geopolitical scholar Abdul Razak Alami noted that as the strategic importance of the Strait of Malacca continues to rise, ASEAN countries need to enhance cooperation to maintain the security and stability of this vital waterway.
Risk Three: Strait Governance Affected by Geopolitics
During the temporary ceasefire between the United States and Iran, Iran demanded transit fees from vessels passing through the Strait of Hormuz, drawing attention from countries along major waterways. Analysts believe that if it becomes widely accepted that littoral states can unilaterally set prices for strait transit, toll collection could evolve into broader institutional friction, undermining global shipping industry confidence in the “default openness” of critical waterways and the sustainable operation of global trade.
Indonesian Finance Minister Sri Mulyani Indrawati said at a seminar in Jakarta on April 22 that Indonesia is located on a vital global trade and energy route, and “vessels passing through the Strait of Malacca do not pay fees,” suggesting Indonesia might consider referencing Iran’s model of collecting transit fees. However, he clarified on April 24, stating that Indonesia would adhere to the United Nations Convention on the Law of the Sea and would not charge fees to vessels transiting the Strait of Malacca.
Abdul Azim Abd Razak, Treasurer of the Maritime Law Association of Malaysia, stated that Malaysia supports the principles of freedom of navigation and unimpeded transit, opposing any attempts to impose transit fees or additional conditions.
Singaporean Foreign Minister Vivian Balakrishnan said during a parliamentary session that Singapore would not participate in any arrangements restricting vessel passage or imposing transit fees, emphasizing that the Strait of Malacca must remain open.
Against the backdrop of the spillover effects of the Iran conflict and great power competition, the policy moves of regional countries are drawing close attention. Indian media reported on April 16 that Indonesia and the United States had originally reached a defense cooperation agreement on April 13, involving granting greater access for U.S. military aircraft to enter Indonesian airspace. However, just as the two countries were about to sign the defense agreement, the provision regarding overflight rights for U.S. military aircraft was excluded.
Azifa Astrina, a regional studies expert at the University of Illinois Urbana-Champaign, believes that the current security architecture of the Strait of Malacca was not designed to limit great power competition. Although the proposed defense agreement between Indonesia and the United States would not immediately disrupt trade, it is structurally potentially disruptive. “When the United States enhances its presence in this region, it will trigger security dynamics that the current system cannot handle.”
