There is a way to punch a very large hole in Russia’s war budget. Europeans only have to emulate President Trump — after seizing a sanctioned tanker carrying Venezuelan crude oil this month, tanker traffic has halted, with vessels bottled up near the coast.
Such a policy would be even easier for Europe. Around 60% of Russia’s seaborne oil exports are transported through the Baltic Sea and the narrow, easily policed Danish Straits. Russia simply could not force its way through.
Shadow-fleet tankers are poorly maintained and dangerous vessels that engage in reckless behavior at sea and manifestly present a huge ecological threat to the Baltic region. They directly fuel an imperial war against a close democratic ally. Despite this, there has been no serious political push to close the Baltic.
Why? Because Russia has frightened the Baltic Sea countries into paralysis.
Officials inside the region have told this author that confidential diplomatic reporting demonstrates deep worries among coastal states about how Russia might respond to a decision to seize tankers.
In Denmark, reluctance is reinforced by fears of reciprocal measures that could harm national commercial interests, including those of Maersk, the huge Copenhagen-based shipping firm.
In practice, Baltic coastal states have converged instead on a selective, risk-based model. It’s a far softer option, but it does have some effect.
Authorities request documentation and proof of insurance, monitor vessel movements, and pose follow-up questions when inconsistencies arise. Controls are not universal, but information-sharing among states is well established by now and central to the approach.
During 2025, the shadow fleet became a more explicit policy focus at the EU level, with the European Union (EU) now playing a more systematic role than NATO. EU actions include expanding sanctions lists, targeting the servicing ecosystem around the shadow fleet, and restricting enabling services.
NATO’s role has been more limited and mandate-constrained, although signaling initiatives have been used to demonstrate resolve. Introduced in January, NATO’s Baltic Sentry is framed primarily around deterrence and critical infrastructure protection, not sanctions enforcement.
But nothing can hide the lack of political resolution. Danish officials have stated that closing the straits is not feasible, and even more modest proposals have tended to stall due to escalation risks and capacity constraints. Efforts to agree on a voluntary, non-binding regional protocol among Baltic Sea states have also struggled.
Draft language has repeatedly been softened to accommodate divergent threat perceptions and risk tolerance. Finland and Sweden have been among the more cautious states, together with Denmark.
Operational constraints become apparent once measures move beyond paperwork. Ships can refuse to provide documents or reject boarding requests, leaving enforcement dependent on how far a coastal state is prepared to escalate. As US action in the Caribbean has shown, this likely means military force, including helicopter-borne boarding teams.
There has been some robust action, but these have been isolated incidents rather than a consistent regional pattern. Examples cited include Estonian encounters involving vessels known as Kiwala and Jaguar, Finnish detention of Eagle S after it successfully sabotaged the Estlink 2 undersea cable, French willingness to intervene in the Bay of Biscay, and a German case involving the confiscation of a drifting vessel in German waters.
Since spring, Russia has adopted more systematic countermeasures to protect shadow fleet operations. These include guidance instructing captains not to comply with coastal state demands, efforts to avoid territorial seas where national powers are stronger, encouragement to record and livestream confrontations, and the presence of armed guards framed as anti-piracy measures. There are also regular Russian naval or maritime patrols in the Baltic. The Swedish Navy recently linked them directly to shadow fleet protection and has also registered uniformed personnel on some of these vessels.
While NATO states have shown restraint, Russia has been taking ever-more aggressive measures. In late September, the Russian Ropucha-class landing ship Aleksandr Shabalin was anchored for days near Langeland, the southern entrance to the Great Belt, a key Danish strait. Danish officials have recorded aggressive maneuvers, radar targeting/weapon pointing, and jamming by other Russian vessels. The Shabalin incident happened at the time when Denmark experienced multiple drone incidents that forced the closure of airports, including Copenhagen, one of Europe’s busiest.
Airspace violations and drone incidents affecting the operation of many of the Baltic Sea states’ airports have also been interpreted as Russian signaling. Western intelligence agencies have not been willing or able to attribute drone flights to Russia or its shadow fleet vessels, though OSINT and other investigative reporting have produced plausible, evidence-based hypotheses. Whether the lack of official attribution reflects policy considerations or limitations in intelligence capability is uncertain.
Russia has also begun to re-use an approach it developed against Ukraine before the all-out war by declaring danger areas closed to normal shipping. On one occasion, this reportedly applied to some areas inside Estonian waters, prompting an Estonian protest note that went unanswered.
Without a significant provocation or crisis — entirely possible given Russian recklessness — future steps will likely include further strengthening of EU sanctions, incremental adjustment of oil price-cap mechanisms, expanded outreach to flag states, greater cooperation along transit routes, and legal innovations such as pre-arranged flag-state consent for boarding.
Legal uncertainty, escalation risk, and economic constraints continue to reinforce a situation in which the Baltic remains open to shadow-fleet logistics, sustaining a critical revenue stream for Russia’s war effort.
So far, it seems that Russia has succeeded in deterring the Baltic Sea nations from even seriously deliberating the possibility of closing the Baltic Sea for the shadow fleet vessels.
Meelis Oidsalu is a former Estonian Undersecretary for Defense and currently works as Chief Editor at the defense outlet balticsentinel.eu. He is a U.S. Army War College graduate, holding a Master of Strategic Studies.
Europe’s Edge is CEPA’s online journal covering critical topics on the foreign policy docket across Europe and North America. All opinions expressed on Europe’s Edge are those of the author alone and may not represent those of the institutions they represent or the Center for European Policy Analysis. CEPA maintains a strict intellectual independence policy across all its projects and publications.
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