Published: May 30, 2026 | Global Security & Commodities Report

SINGAPORE STRAIT — Two months after U.S. President Donald Trump implemented a strict maritime blockade on all Iranian ports under National Security Presidential Memorandum-2 (NSPM-2), billions of dollars in illicit crude oil continue to flow through Southeast Asia.

A sprawling “shadow fleet” of aging, rusted tankers is successfully exploiting international legal loopholes and using advanced tactical deception in the world’s busiest shipping corridor, fundamentally undermining Western efforts to choke off Tehran’s primary source of sovereign revenue.

Data compiled by satellite tracking firms and maritime monitoring groups reveals that this illicit trade is not just persisting—it is thriving under a structured, sophisticated framework of evasion.

A “Brazen” Floating Pipeline to China

Off the southeast coast of Malaysia, an estimated 150 million barrels of sanctioned oil are currently sitting on the water, spread across more than 120 tankers tied directly to the National Iranian Oil Company (NIOC). According to data from United Against Nuclear Iran (UANI), at least 42 complex ship-to-ship (STS) transfers of Iranian oil have occurred in this specific sector since late February, acting as a critical economic buffer for Tehran.

The destination for this crude is almost entirely the independent “teapot” refineries of Northern China, specifically pumping through ports in Shandong and Dalian. The scale of this trade is unmatched globally:

• Global Choke Point: The tankers transit from the Persian Gulf directly through the Strait of Malacca and the Singapore Strait.
• Massive Volume: In the first half of 2025, approximately 23 million barrels of oil passed through this artery every day.
• Market Share: This traffic represents nearly one-third of all global seaborne oil trade, making individual rogue vessels nearly impossible to intercept without bringing local commercial shipping to a standstill.

The Playbook of Deception

To blend seamlessly into local heavy maritime traffic, shadow fleet operators use a predictable, highly sophisticated playbook designed to give buyers plausible deniability: