Tanker Tricks on the High Seas Expose Shadowy Russian Oil Trade

On a sunny day off the southern coast of Greece last week, two aging tankers nestled next to each other while one pumped oil to the other. As far as global satellite tracking systems could tell, it never happened.

The deviation between real and electronic locations — measured in this case at over four miles — wasn’t a glitch, but a deliberate deception that’s part of a sophisticated system to keep sanctioned Russian fuel flowing, often at prices that are higher than western powers would like.

The practice of giving fake coordinates to the automatic identification system, known as AIS, is called ...