On May 18, 2025, Russian authorities detained a Greek-owned oil tanker called the Green Admire shortly after it left the Estonian port of Sillamae. The vessel, flying under a Liberian flag, was following a well-established route through Russian territorial waters—part of a maritime safety agreement between Russia, Estonia, and Finland. It was carrying shale oil bound for Rotterdam and used this channel to avoid the shallow and dangerous waters off Estonia’s coast. Despite all this, Russia decided to seize the ship, making it the first time such a detention has happened under these circumstances.

Estonia didn’t take the move lightly. The government immediately announced it would reroute all shipping traffic from Sillamae exclusively through Estonian waters, no longer relying on the shared route. The Estonian Foreign Minister described Russia’s behavior as “unpredictable” and wasted no time in briefing NATO allies. The whole ordeal is part of a bigger pattern that’s been unfolding in the Baltic Sea.

Just three days earlier, the Estonian navy tried to stop an unregistered tanker they suspected was part of Russia’s “shadow fleet”—a ragtag group of older ships Moscow uses to dodge Western sanctions and keep oil flowing under the radar. That operation was cut short when Russia scrambled a fighter jet, which brazenly crossed into Estonian airspace. For a NATO country like Estonia, that’s not just a nuisance—it’s a serious escalation.

These moves fit a broader trend: Russia using hybrid tactics to keep its energy exports alive and keep the West off balance. Between aggressive flyovers, underwater sabotage, and now detaining tankers on agreed routes, the Kremlin is turning up the heat in the Baltic. Estonia’s decision to reroute shipping isn’t just about avoiding conflict—it’s a signal that the Baltics are fed up with Russia’s games and are ready to take more control of their own backyard.

For NATO, this is yet another flare in an already tense region. With military and commercial lines increasingly blurred, the risk of an accidental clash keeps growing. Everyone’s watching what happens next, but one thing’s clear: the Baltic Sea is becoming a pressure point in the standoff between Russia and the West.