Southeast Asian governments are failing to respond as a bloc to the severe disruption in oil, gas and commercial shipments through the Strait of Hormuz. Malaysia, Thailand, the Philippines and Vietnam have each moved to secure passage through separate channels with Iran. Singapore, by contrast, has taken a sharply different position, refusing to negotiate over what it regards as a right of transit.
Collective action would have served the region better, but tighter supplies, delayed shipments and rising prices have pushed governments towards individual deals with Iran. The result is a weaker regional response and a shift away from access as a right towards access secured case-by-case. Washington’s restrictions on shipping linked to Iranian ports have made that shift harder to ignore.
That matters because Southeast Asia’s prosperity still depends on sea lanes remaining open under ordinary commercial conditions. Singapore’s position is straightforward: passage through an international strait is not supposed to depend on permission, bargaining or payment. Singapore has treated that principle not as an abstract legal claim but as the premise on which its prosperity was built. The same principle underpins the large trade flows through the Strait of Malacca and therefore Singapore. Once access must be negotiated in one major strait, the implications do not stop there.
Other governments in the region have made a different calculation, though not because they reject free transit itself. Faced with tighter fuel supplies and rising domestic prices, they have moved to secure passage first and left questions of precedent for later. Thailand announced an agreement with Iran for Thai tankers to transit Hormuz safely. Malaysia secured safe passage for one of its stranded commercial vessels after diplomatic engagement. And the Philippines received Iranian assurances regarding the safe passage of Philippine-flagged vessels, energy supplies and Filipino seafarers through the strait. Singapore has more scope to hold on to the free-transit principle publicly because it has spent decades building reserves, diversifying supply and preparing institutions to manage disruption. Not all its neighbours have the same capacity.
Iran’s conduct helps explain why the region has fractured along these lines. Tehran is not simply threatening shipping through the Strait of Hormuz; it appears willing to make passage conditional on political alignment, prior coordination or compliance with procedures it increasingly expects vessels to follow. Years under financial sanctions taught Iran how leverage works in an interdependent system. The aim is not simply to disrupt traffic but to influence who moves, when and on what terms. Financial pressure rarely cuts firms off directly. It makes routine transactions uncertain enough that commerce continues on worse terms, through less transparent channels and with greater risk. Behaviour changes once access becomes unpredictable rather than closed.
That is now happening in Hormuz. A sea lane can remain formally open while becoming much harder to use in practice. In a narrow strait, uncertainty alone is enough to make shipowners, insurers and governments act more cautiously. Some recent transits have depended on naval protection, prior coordination or Iran’s own clearance procedures rather than ordinary passage. Washington’s restrictions do not restore normal transit; they add another layer of political control. The strait is now under pressure from both the United States and Iran, each affecting different vessels for different political purposes. The waterway is being managed and contested rather than simply kept open.
The effects extend well beyond the strait. Insurance costs rise, freight markets tighten, inventories are managed more cautiously, and pressure accumulates in electricity, food and industrial inputs. Even if the Strait of Hormuz were to reopen, supply conditions would not return quickly to earlier levels. Southeast Asia is therefore trying to cope with more than a Gulf disruption.
A similar pattern of regional fragmentation appeared earlier under tariff pressure from Washington. Governments that spoke of resilience and strategic autonomy nonetheless negotiated separately because access to the American market was too important to risk for the sake of a common line.
The pattern has now reappeared through shipping rather than tariffs. The Association of Southeast Asian Nations has built frameworks for connectivity and energy resilience over many years, and at its May 2026 summit, leaders agreed in principle to establish a Maritime Centre in the Philippines, with some officials linking it to broader concerns about maritime access and freedom of navigation. However, many regional agreements still rely on bilateral links rather than shared arrangements, infrastructure or coordinated emergency reserves. When access itself comes under pressure, member states fall back on national responses and calculate their own tolerance for disruption.
Each separate arrangement makes it harder to restore open access as the default. What was once taken for granted can no longer be relied upon. The lesson from the Strait of Hormuz is that access itself can become a tool of pressure. For Southeast Asia, the challenge is no longer only disruption in the Gulf. Vital routes may increasingly depend on political bargaining rather than ordinary commercial use. That poses a serious problem for a region whose prosperity rests on open sea lanes and whose governments still struggle to act in concert when those sea lanes come under strain.
