Russian “shadow fleet” tanker without valid registration slips through Estonian waters at night to avoid seizure

The oil tanker Marathon, part of Russia’s so-called “shadow fleet,” attempted to pass unnoticed through Estonia’s Exclusive Economic Zone (EEZ) during nighttime hours in order to avoid possible interception and inspection. According to data analyzed by The Insider in collaboration with Starboard Maritime Intelligence, the vessel had no valid registration at the time — a fact that would have given Estonian authorities the legal grounds to board and detain the ship.

Estonia had previously detained the tanker Kiwala and attempted to stop the Jaguar — both of which are part of Russia’s “shadow fleet,” a collection of aging, poorly insured vessels that transport oil in circumvention of the $60-per-barrel price cap introduced by the G7, the EU, and Australia in 2022. The fleet has allowed the Kremlin to continue to line its coffers and finance the ongoing full-scale invasion of Ukraine, which entered its fourth year in February 2025.

The Marathon crossed the Baltic Sea between June 11 and 13. Before entering Estonian waters, the vessel slowed down significantly and remained nearly stationary for approximately 28 hours. It then sped through Estonia’s EEZ shortly before sunrise — at around 4:00 a.m. UTC on June 13.

During the crossing, Marathon did not anchor or stop and proceeded directly toward Russia. No boarding or escort by Estonian authorities was observed.