Iran’s Tanker Fleet Used Malaysian Waters During the Ceasefire. Now the Window Is Shut.

Johor Strait, Malaysia. During the six-week ceasefire between the United States and Iran, a group of sanctioned Iranian crude tankers gathered at an anchorage zone off Malaysia's coast and transferred oil between vessels.

The zone is known as the Eastern Anchorage, positioned off the eastern tip of Johor in international waters. Malaysia has acknowledged that ship-to-ship transfers conducted there exploit a gap in maritime jurisdiction. Vessels at international anchorage points fall outside the direct reach of Malaysian port authority enforcement.

SEVIN, a Suezmax crude tanker placed on the US State Department sanctions list in February 2026, was among the vessels identified at the anchorage during this period by analysts at United Against Nuclear Iran. UANI tracked more than 20 Iranian tankers at the site across reports published between July 6 and July 20.

The ceasefire memorandum between Washington and Tehran took effect June 17. The US Navy suspended enforcement of its blockade on Iranian oil exports for the duration. That pause was the opening the tanker fleet moved through.

The blockade came back on July 14. The fleet dispersed. SEVIN was recorded departing in ballast -- without cargo -- around July 20, per UANI's final update on the vessel group.

Ship-tracking data showed a surge in searches for SEVIN in the days after UANI published the vessel identities, as sanctions analysts and maritime monitors picked up the trail.

For the wider shipping context, our guides explain how conflicts change shipping routes, tracking vessel activity by region, and why ships may be absent from a tracking map.