KSE Institute presents a new study on ship-to-ship (STS) transfers of Russian oil. The authors analyze these operations from Q1 2025 to Q2 2026, examining their geography, their role in Russia’s seaborne oil exports, and the relative importance of Russian oil, as well as the ecosystem and sanctions coverage of the tankers involved.

Russian crude oil STS activity is concentrated in a small number of locations. Nakhodka Light in the Pacific Ocean, Eastern Outer Port Limits (EOPL) off the coast of Malaysia, and Offshore Hong Kong accounted for 62% of all STS transfers involving Russian crude oil between Q1 2025 and Q2 2026. Nakhodka Light was the largest STS hub, accounting for 179 operations, or 39% of the total.

The geography is different for oil products. The zone near the Suez Canal, Cyprus Light, and EOPL accounted for 64% of all STS transfers involving Russian oil products. The geography has also shifted since 2025, with activity moving away from established Mediterranean locations and expanding at new hubs such as around Gibraltar and Nakhodka Light.

STS transfers generally have accounted for an average of ~15% of Russia’s seaborne oil exports. In Q1 2026, their share temporarily increased to around 19%. One factor may have been US sanctions imposed on Rosneft and Lukoil: following these sanctions, STS transfers involving Russian oil sold by the two companies approximately doubled.

Between Q1 2025 and Q2 2026, the authors identified 799 unique tankers involved in STS operations. Of these, 438 of them (55%) currently meet KSE Institute’s definition of the shadow fleet — meaning they do not have links to G7+ services such as ownership, management, flagging, or insurance.

STS transfers facilitate the consolidation of Russian oil cargoes from smaller tankers onto larger vessels for onward transportation. At the same time, after the transfer, cargo often moves onto tankers that are not designated. In Q2 2026, designated tankers accounted for 94% of crude oil volumes supplied to STS locations, while designated tankers also received 55% of the volumes transferred from them. 

Sanctions coverage is lower for tankers involved in STS transfers of Russian oil products. In Q2 2026, designated tankers accounted for 20% of oil products volumes supplied to STS locations, while designated tankers also received 17% of the volumes transferred from them. Throughout the observation period, their share remained below 30% on the supplying side and at or below 20% on the receiving side.

Large tankers play an important role in STS operations involving Russian oil. Among the 50 very large and ultra large crude carriers (VLCCs/ULCCs) receiving Russian oil at STS locations, 33 are currently shadow fleet vessels, but only five are designated by at least one jurisdiction. STS transfers play an important role in separating Russia’s heavily sanctioned crude oil export fleet from the onward transportation network, allowing cargo to move from designated tankers onto a substantially less-sanctioned and more diverse pool of vessels for onward delivery to final buyers.