A blockaded scene emerged near the Bosphorus as oil tankers found themselves halted in the waterway off Turkey’s coast. By December 5, observers noted nineteen ships stuck in the flow of traffic, a gridlock that tightened as the day progressed. Western powers had set a price ceiling on Russian oil, while Turkey pressed insurers to guarantee full coverage for every vessel passing the straits. The result was a standing queue of tankers within Turkish territorial waters, and Ankara requested written proof that insurance would cover spills and other emergencies. Insurers, represented globally by P&I Clubs, argued that the Turkish demand stretched beyond standard requirements for marine liability coverage, touching on practices that were not ordinarily part of routine transit insurance in the region.
Tankers, anchored in the Bosphorus and the nearby Dardanelles, connect Russia’s Black Sea ports with markets worldwide. The Financial Times noted that the first tanker had reached the strait on November 29, nearly a week before the new restrictions began, illustrating how quickly events developed. The disruption appeared to echo through fuel supply chains, with the potential to ripple across global oil markets if sanctions on Russian crude continued to tighten the route and the capacity to move cargoes remained constrained.
By December 6, Russian-flagged vessels showed up among those stalled in the Bosphorus. Monitoring data from Marinetraffic listed ships such as Kapitan Barmin, General Skobelev, Lady Maria, Lady Aria, Caminero, and Roschem 2 blocked from passing from the Black Sea. The majority of the jammed vessels were Turkish-owned, according to the same tracking service, underscoring how local fleets were intertwined with this wider global disruption.
On December 7, concerns rose in Moscow as the Russian Foreign Ministry described the congestion and said that the scope of the issue would be assessed from both transport and insurance perspectives. Deputy Foreign Minister Alexander Glushko warned that state intervention could become necessary if the situation persisted, signaling a possible escalation beyond private insurance arrangements. At the same time, Deputy Prime Minister Alexander Novak, who oversees energy policy, indicated that Russia would pursue new strategies to secure raw materials in response to the Western price caps and shipping restrictions being put in place by Western partners.
Analysts from Bloomberg estimated that at least 18 million barrels of oil were tied up in tankers off the Turkish coast on December 6, representing roughly one-fifth of daily global production. The agency highlighted that most of the stranded cargoes involved Kazakh shipments, with a sizable portion linked to Tengizchevroil operations. Kazakh officials suggested that a meaningful portion of the jammed tonnage had direct ties to Astana, and that the total count of anchored vessels approached twenty-one, including several associated with Tengizchevroil.
Late on December 8, an official Turkish statement reaffirmed the FT’s reporting: ships whose crews could not present insurance documentation would not be allowed to pass through the straits. The Ministry of Transport and the General Directorate of Maritime Affairs announced strict measures aimed at protecting the straits from potential disasters, reminding shipowners that since 2002 they are required to carry P&I insurance certificates to cover accidents, pollution, or other damages. Despite such warnings, Turkish authorities dismissed media reports of a broad coastline buildup, noting that about 15 tankers were at anchor at that time, 11 of which were destined for EU markets, and that the larger concern focused on ensuring safe, auditable transit under evolving regulatory conditions rather than any indiscriminate congestion.
These developments illustrate how tightly fluid disruptions in oil transport can align with policy moves on price caps and insurance requirements. As global markets watch closely, the balance between sanctions enforcement, insurer risk assessments, and the operational realities of cross-border shipping continues to shape the movement of crude through one of the world’s most strategic waterways.