Russian oil volumes carried by US-sanctioned vessels have risen in recent months, weakening an earlier collapse in activity.
Brookings researchers say American designations once cut average monthly volumes by more than 80%, but enforcement credibility is fading.
The trend raises concerns for sanctions coordination, maritime safety and the integrity of global commodity trade.
Sanctioned Tankers Return to Russian Trade
The deterrent effect of United States sanctions on Russia's shadow oil fleet is weakening as sanctioned tankers return to carrying larger volumes, according to analysis by Brookings researchers Robin Brooks and Ben Harris.
Their findings suggest that designating vessels can sharply restrict trade, but only while companies, ports, insurers and buyers believe violations will trigger meaningful secondary sanctions.
Monthly Russian crude and refined-product exports on US-sanctioned tankers fell from an average of 35 million barrels in 2023 and 2024 to 7 million barrels in 2025, a decline of more than 80%.
Volumes accelerated again in recent months, most visibly in July 2026.
- The researchers cautioned that August data were incomplete, so the durability of the reversal was not yet certain.
Europe Expands Lists as America Stands Still
The divergence between allied sanctions lists is widening.
- The United States had sanctioned 216 vessels, a total unchanged since January 2025.
- The European Union's count reached 671 after additions in July
- The United Kingdom reached 627 after six vessels were added on August 6.
Across all three jurisdictions, the total number of sanctioned ships rose from 734 in July to 740 in August.
Coordination has improved in some areas:
- Sanctions affect 178 ships across the three jurisdictions.
- 395 were covered by both the EU and UK.
- However, 524 tankers sanctioned by European authorities had not been designated by the United States.
Brookings argues that this gap matters because US secondary sanctions can expose counterparties to American action, giving a US designation greater deterrent power.
Coordinated Enforcement Can Restore Market Integrity
A credible sanctions regime can force traders back toward vessels with transparent ownership, recognised insurance and stronger safety oversight.
- That would make it harder to move oil outside the G7 price cap and reduce the environmental and financial risks associated with ageing or poorly insured tankers.
- Coastal states, port authorities and seafarers all bear the consequences when opaque shipping networks fail.
The lesson extends beyond Russia.
- Sanctions work through networks of refiners, banks, brokers, flag registries, ports and ship-to-ship transfer providers.
- If those actors conclude that a listed vessel can trade without consequence, the formal designation loses practical force.
- Consistent enforcement, rather than the length of a sanctions list alone, determines whether compliance becomes the safer commercial choice.
Investors and commodity buyers also face governance questions.
- Cargo provenance, vessel ownership, insurance and environmental liability can create legal and reputational exposure long after a transaction closes.
Banks and trading houses need controls that examine the whole voyage and payment chain, including intermediaries and transfers at sea.
- Comparable due-diligence standards would make it harder for risk to migrate between jurisdictions.
Authorities Need Aligned Lists and Consequences
Brooks and Harris recommend that the United States designate the 524 vessels already sanctioned by the EU and UK but not by Washington.
- They also call for stronger use of secondary sanctions against entities that handle cargoes carried by listed tankers.
- A proposed 2026 sanctions bill could reduce the evidentiary burden when European allies have already designated a vessel.
Any expansion should be paired with current ownership data, clear guidance and due process.
- Authorities should also strengthen port-state inspection, beneficial-ownership transparency and liability rules for spills or collisions.
For African maritime and energy markets, consistent standards matter: fragmented enforcement can redirect higher-risk vessels and opaque trading practices toward jurisdictions with less monitoring capacity.
Path Forward – Restoring Credibility Through Coordinated Sanctions Enforcement
The United States, EU and UK need aligned vessel lists, active secondary-sanctions enforcement and better information on ownership and cargo networks.
Designations without credible consequences will continue to lose force.
Port safety, insurance accountability and environmental protection should accompany financial restrictions.
This wider approach can reduce evasion while limiting the risk that opaque, ageing vessels shift into less protected maritime markets.
Culled from: The fading efficacy of US shadow fleet sanctions | Brookings
