"I hope that it will be in place by December," EU foreign policy chief Javier Solana said, as the bloc's defence and foreign ministers held talks in Brussels.
The so-called EUNAVOR operation will be made up of at least seven ships, including three frigates and a supply vessel. It will also be backed by surveillance aircraft.
The mission will be run from a headquarters at Northwood near London, with contributions from France, Germany, Greece, the Netherlands and Spain, with Portugal, Sweden and non-EU nation Norway also likely to take part.
"Our participation in the Somalia project is an important one," British Foreign Secretary David Miliband told reporters.
"This is obviously a very challenging project but one that European leaders are approaching with real humility as well as determination," he said.
The EU initiative was taken after Somali President Abdullahi Yusuf Ahmed urged Somalis and the international community to combat rising piracy off the lawless nation's waters.
Last month, a maritime watchdog said Somali pirates were now responsible for nearly a third of all reported attacks on ships, often using violence and taking hostages.
On Friday, Somali pirates seized a Danish-managed cargo ship with 13 crew.
NATO warships recently arrived in the region in a bid to secure the maritime delivery of food aid to the civilian population of Somalia, where a deadly civil conflict continues to rage.
India and Russia have also sent ships to the area on anti-piracy duties.
The International Maritime Bureau said 63 of the 199 piracy incidents recorded worldwide in the first nine months of this year occurred in the waters off Somalia and in the Gulf of Aden.
The Somalian figure is almost double that of the same period last year.
Somalia's well-organised pirates prey on a key maritime route leading to the Suez Canal through which some 30 percent of the world's oil is transported.
The pirates operate high-powered speedboats and are heavily armed, sometimes holding ships for weeks until they are released for large ransoms paid by governments or owners.
France, which has a major military base in neighbouring Djibouti, is so far the only country to have used its firepower against the pirates, in April and September operations following hostage-takings.
Under the mission's rules of engagement, EU nations that capture any pirates will not be allowed to hand them over to a state where suspects could face the death penalty, torture or degrading treatment.