Somali pirates have hijacked a ship some 1,800km (1,100 miles) from their bases - closer to India than Africa, the EU naval force says.
Cdr John Harbour said the attack, on a Turkish-owned ship, marked a major increase in the pirates' range.
He said the EU force had launched a new strategy which was pushing the pirate gangs further afield.
Somalia has been riven by civil war and unrest since 1991, allowing the pirates relative impunity.
Some of the pirates leaders have amassed fortunes by holding ships for ransom, and the Gulf of Aden has become one of the most dangerous shipping lanes in the world.
But Cdr Harbour said the EU force had disrupted about 17 pirate attacks in the past three weeks.
"The EU, Nato and combined maritime forces have been taking the fight to the pirates," he told the BBC.
"We've tried to stop them getting off the beaches; when they've got to the Indian Ocean, we've been very aggressive in targeting the individuals and disrupting pirate activity."
The ship, named as the MV Frigia, was heading east but has now turned around.
The EU said it was sailing west and appeared to be heading for one of the known pirate ports in Somalia.
The cargo ship has a 21-strong crew - 19 Turks and two Ukrainians.