A rising number of Japan-bound crude tankers are loading Middle East barrels without crossing the Strait of Hormuz, according to a Bloomberg report Tuesday that cited shipbrokers and tanker-tracking data.

The carriers are conducting ship-to-ship (STS) — vessel-to-vessel cargo transfers at anchor — in the Gulf of Oman, offshore Oman and at the UAE port of Fujairah. None of the cited vessels entered the Persian Gulf proper, the report said. The shift marks a partial return for Japan-owned and Japan-bound tankers that had steered clear of the broader Middle East region since the Iran war began, per the shipbrokers Bloomberg quoted.

How does the rerouting work?

The geography reshapes a single voyage into two legs. A Persian Gulf-loaded tanker discharges to a waiting Japan-bound vessel in the Gulf of Oman, swapping one hull's cargo onto another at anchor outside Hormuz.

The Japan-bound tanker then sails east without passing through the narrow chokepoint between Iran and Oman. Persian Gulf-loaded vessels exit via the same offshore waypoint after their cargoes shift, the shipbrokers told Bloomberg. The pattern, the brokers said, lets refiners keep Middle East crude in their supply mix while crews avoid a transit zone Iranian forces have intermittently threatened.

Tanker operators who pulled out of the region when hostilities escalated are now willing to anchor off Oman's coast or at Fujairah's roadstead — the sheltered stretch where offshore transfers occur.

What's changed at the buoys?

STS work isn't new to the Gulf of Oman. Fujairah has long hosted offshore lightering, the anchor-based top-up of partly-empty vessels that traders have used for years to manage draft and routing constraints.

What changed, per the tanker-tracking data Bloomberg cited, is who's showing up. Most Japan-owned and Japan-bound tankers had avoided the region since the war began. Their return to Fujairah-area waters signals a partial, broker-confirmed reopening of Gulf crude flows to Japanese refineries.

The reservation: STS doesn't eliminate Hormuz exposure for the Persian Gulf-loaded vessel. It just shifts that exposure to a different hull at an Omani or UAE anchorage.

What the report didn't disclose

Bloomberg did not name the Japanese refiners booking the cargoes. It also did not put a number on the rising share of Japan-bound tonnage now lifting STS volumes. No pricing spread between STS-loaded and Hormuz-loaded barrels of equivalent grade surfaced in the report.

That omission is itself the story. A persistent public spread would give traders a clean read on the risk premium now embedded in Gulf crude under the new routing. Its absence suggests refiners are absorbing exposure without yet paying a transparent premium for the privilege.

Where shipbrokers name rising volumes, traders usually name a dollar figure. Tuesday's report named neither.

What's the watch item?

Any confirmed AIS (Automatic Identification System) signal — the mandatory transponder ping every commercial vessel broadcasts — showing a Japan-owned tanker in Hormuz would reset this pattern overnight. Persian Gulf crude to Japan now travels via STS liftings off Fujairah, until that signal flips, or until diplomatic channels reopen and the routing choice softens.

The follow-up also matters: a published STS-versus-Hormuz price differential would tell refiners — and traders — how much real risk premium this quieter reroute is actually carrying.

Bottom line: Japanese refiners are buying Gulf barrels they once wouldn't touch, but they're buying them around the strait, not through it — a quiet broker-confirmed rerouting, not a strategic pivot.