WSJ exposes Iran's illegal oil black market operating off Malaysia's coast

An investigation by the Wall Street Journal has revealed a shadowy offshore black market operating 70 kilometres from the Malaysian coast, where tankers carrying Iranian crude oil wait to transfer their cargo to vessels bound for Chinese refineries. The area, known as the Eastern Outer Port Limits, functions as a legal no-man's-land enabling Iran to circumvent international sanctions.

Seventy kilometres off the coast of Malaysia, a stretch of international waters known as the Eastern Outer Port Limits has become a key hub in a sophisticated sanctions-busting operation that keeps Iranian crude oil flowing to Chinese refineries. A Wall Street Journal investigation has documented — in words and images — how tankers laden with Iranian oil queue up in this maritime grey zone, waiting to transfer their cargo to other vessels headed for China.

A floating no-man's-land

The Eastern Outer Port Limits, informally translating to the outer eastern boundary of the port zone, sits just far enough offshore to operate in regulatory ambiguity. Heavily laden tankers, visibly sitting low in the water under the weight of their cargo, anchor in the area and conduct ship-to-ship transfers that are designed to obscure the origin of the oil before it reaches its final destination.

The operation is a critical lifeline for Iran, which remains under sweeping Western sanctions targeting its oil exports. By routing crude through intermediary vessels and obscuring the paper trail, Iranian oil effectively re-enters the global market with its origins masked — a practice commonly referred to as "dark fleet" shipping.

China the key destination

China has emerged as the dominant buyer of Iranian oil in recent years, with Chinese independent refiners — known as "teapot refineries" — purchasing discounted Iranian crude despite the sanctions risk. The Malaysian offshore zone offers a convenient transfer point, geographically positioned between the Persian Gulf and Chinese ports.

The Journal's investigation highlights how this black market has grown into a well-organised system involving dozens of tankers, specialised brokers, and falsified shipping documents. Western governments and sanctions enforcement agencies have struggled to shut down the network, partly because the transfers occur in waters where jurisdiction is contested or enforcement capacity is limited.

Sanctions under pressure

The revelations put renewed pressure on both Washington and European capitals to tighten enforcement of Iran-related sanctions. Critics argue that the scale of the operation — visible in satellite imagery and ship-tracking data — suggests that existing measures are failing to meaningfully curtail Iranian oil revenues, which in turn fund the country's military and political activities across the Middle East.