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At least three Indian oil refiners and a global energy major plan to stop using vessels on Iran’s new blacklist, including for ship-to-ship transfers, due to security concerns, four sources with direct knowledge of the matter said this week.
Tehran announced on Sunday (August 23, 2026) a blacklist of 45 ships, it said, had broken its rules for crossing the Strait of Hormuz, and would take action against any vessels transferring loads with them, escalating its threats over the key waterway for global energy supplies six months into the U.S.-Israeli war on Iran.
Iran’s announcement appears designed to impede the so-called shuttle runs Gulf oil producers such as the United Arab Emirates and Saudi Arabia have undertaken with dedicated tankers to move oil from the Gulf through Hormuz for unloading through STS transfers in the Gulf of Oman onto ships to end-users.
The shuttle runs have kept alive oil flows from West Asia that have been curtailed by Iran’s clampdown on shipping through the strait because of the war.
The named vessels could be fined, detained and have their cargoes confiscated, according to a post on social media website X from the Persian Gulf Strait Authority, a new body set up by Iran to manage the strait.
“We will avoid our chartered vessels dealing or STS or anything to do with non-compliant ships for Middle Eastern cargoes,” said one of the sources, who works at an Indian refinery.
The sources declined to be identified because of the sensitivity of the issue.
Some of the tankers Iran listed are owned or chartered by Saudi Aramco and Abu Dhabi National Oil Co (ADNOC). The ships have been used for shuttling crude, refined products and liquefied natural gas (LNG) out of the Gulf for STS transfer off Fujairah in the UAE or Sohar, Oman, according to shipping data.
Saudi Aramco and ADNOC declined to comment.
Ana Subasic, a trade risk analyst at shiptracking firm Kpler, said the most compliance-sensitive buyers are expected to avoid these vessels moving forward, but the trade is more likely to reroute through alternative tonnage, counterparties or transfer locations than disappear altogether.
Internal discussions
Several charterers and shipping firms are discussing internally whether to continue their STS operations or not and are evaluating Iran’s warning, multiple other trade and shipping sources said, with one of them, a Gulf crude buyer, saying it would be safer to buy oil on a delivered basis shipped to a final destination instead of free-on-board at STS locations in the Gulf of Oman.
Those sources also declined to be identified because of the sensitivity of the matter.
“Our internal departments are still in discussion on how to proceed with crude deliveries from the Strait of Hormuz via ship-to-ship transfers in the long term,” said Formosa Petrochemical Corp President KY Lin.
Iran has previously attacked several of the tankers, including the Wedyan, Mombasa B and Al Bahyah.
Two of the 12 very large crude carriers on Iran’s blacklist were no longer giving their location through their automatic identification systems (AIS) by Tuesday after the list was released, while the rest have had their AIS transponders switched off for weeks.
“The key issue is contagion,” Kpler’s Subasic said.
“If Iran follows through on threats to penalize vessels that conduct STS transfers with blacklisted tankers, that should narrow the pool of willing shipowners, charterers and buyers, particularly among firms with material Gulf exposure, while increasing due-diligence requirements and potentially freight, insurance and risk premia.”
Published – August 26, 2026 01:00 pm IST
