[This opinion piece was contributed by Ahn Young-jip, the Adviser to the Korea National Diplomatic Academy, Former Ambassador to Singapore]
As the recent Middle East war raises the specter of a blockade of the Strait of Hormuz and even the possibility of transit tolls being imposed there, the international community has once again been forced to confront the strategic significance of maritime straits. What happens in Hormuz does not remain confined to the Gulf. It is deeply interconnected with other international straits and so-called global choke points that sustain the arteries of world commerce.
The 1982 United Nations Convention on the Law of the Sea expanded territorial waters from three nautical miles to twelve. As a consequence, 116 straits that had previously been used freely for international navigation suddenly came within the territorial seas of coastal states. This created the danger that previously unrestricted transit could become subject to sovereign limitations.
To resolve this dilemma and preserve a balance between the interests of coastal states and user states, the international community introduced the legal concept of “transit passage” for straits used in international navigation. Under this framework, ships, submarines, and aircraft are guaranteed the right of continuous and expeditious passage through such straits and the airspace above them without interference.
Should transit passage in the Strait of Hormuz ever be denied — or should tolls be imposed upon vessels exercising that right — it would constitute a direct challenge to the very foundations of the Law of the Sea Convention. More importantly, it would establish a dangerous precedent capable of destabilizing the legal order governing international straits across the globe.
For Koreans, the Strait of Malacca and the Singapore Strait are far more familiar and, in many respects, even more strategically sensitive. Every day, volumes of crude oil and refined petroleum products exceeding those transiting Hormuz pass through these waterways. The flow of general cargo is incomparably greater.
More than 30 percent of South Korea’s import and export cargo, as well as nearly 90 percent of its crude oil imports, move through these straits. Moreover, while the narrowest point of Hormuz measures roughly 39 kilometers across, the narrowest section of the Singapore Strait is barely 3.7 kilometers wide. From a purely strategic perspective, the Malacca–Singapore route is therefore significantly more vulnerable.
It is for this reason that the recent suggestion by Indonesia’s finance minister that tolls should be imposed on vessels transiting the Malacca Strait attracted such attention. The proposal was ultimately withdrawn amid opposition from Malaysia and Singapore, as well as criticism within Indonesia itself. Yet if the maritime order governing Hormuz were fundamentally altered, there can be no guarantee that the attitudes of other coastal states would remain unchanged.
The Taiwan Strait represents another critical choke point. More than 45 percent of South Korea’s import and export cargo and over 85 percent of its imported crude oil pass through these waters. Although its narrowest point is approximately 130 kilometers wide, nearly half of the world’s container ships traverse the strait, making it one of the busiest maritime corridors on Earth.
Should tensions between China and Taiwan escalate into armed conflict, or should the strait become blocked for any sustained period, the economic consequences for both Korea and the global economy would be almost impossible to overstate.
The present crisis in Hormuz, therefore, raises a series of fundamental questions regarding the nature of maritime straits themselves.
Can coastal states impose transit fees on international straits in the same manner that tolls are levied on the Suez Canal or the Panama Canal? Who truly owns a strait? And who possesses the right to control it?
The distinction is crucial.
Artificial waterways such as the Suez and Panama canals were constructed commercially within the sovereign territory of individual states, and international agreements explicitly recognize their right to collect tolls. International straits are fundamentally different. In such waterways, the right of transit passage — far stronger than the innocent passage accorded to foreign ships within territorial seas — applies.
International straits are therefore not spaces subject to the unrestricted sovereign control of coastal states. They are, in effect, global public goods in which uninterrupted passage is guaranteed for the international community as a whole.
Yet reality is never governed by law alone.
International law provides norms and principles, but effective control over maritime straits is profoundly shaped by military power and geopolitical realities. When coastal states militarize islands, reefs, or surrounding maritime terrain — or attempt to extend control beyond what international law permits — the legal order painstakingly constructed by the international community comes under severe strain.
This is precisely the challenge now emerging before us.
What, then, are the implications for South Korea?
South Korea is one of the world’s quintessential maritime trading nations, heavily dependent upon imported energy and raw materials. Any disruption to energy flows passing through Hormuz or Malacca would inflict enormous damage upon the Korean economy. Likewise, South Korea’s trade is deeply dependent upon East Asian sea lanes, including the Taiwan Strait.
For Seoul, this issue must therefore be understood not as a distant regional dispute, but as a structural risk directly linked to national survival.
First, South Korea must consistently support the principles of freedom of navigation and transit passage, which form the foundation of the international maritime order.
Second, Korea must accelerate efforts to diversify its energy supplies and supply chains in order to reduce excessive dependence upon any single maritime corridor.
Third, the country must strengthen both its naval capabilities and its capacity for international maritime cooperation to protect vital sea lanes.
Above all, however, Korea requires strategic balance. Rather than aligning reflexively with the position of any particular state, Seoul’s long-term national interest lies in maintaining a principled stance grounded in international law and multilateralism.
The message connecting Hormuz, Malacca, and the Taiwan Strait is unmistakably clear.
When rules collapse, middle powers and trading nations suffer first — and often suffer most.
Maritime straits are not the exclusive property of any single nation. They are lifelines of the international community itself.
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