Foreign policy chief Javier Solana said the EU warships will arrive Monday, and the hand-over with the NATO force will take place Dec. 15.
Officials said France, Greece, Germany and Britain will provide ships for the naval contingent, and France and Italy will provide patrol aircraft.
The task force _ codenamed Operation Atalanta _ will be the EU's first naval operation. It will have the same duties as the NATO mission, including escorting cargo vessels, protecting merchant ships and deterring pirate attacks.
"These tasks will be done with very robust rules of engagement," Solana told reporters on the sidelines of a meeting of NATO foreign ministers.
The ministers agreed on Monday to ask the U.N. Security Council to clarify the legal issues involved in the anti-piracy effort. They will discuss on Wednesday whether to deploy a follow-up anti-piracy mission to assist the EU ships.
Under the current U.N. mandate, the international fleet operating off the Horn of Africa has not been able to board ships seized by the pirates in order to free their hostages.
German Foreign Minister Frank-Walter Steinmeier welcomed the EU deployment.
"I think this is necessary, and the past days have shown that the presence on the African coast has already saved a few ships from being hijacked," he said as he arrived for the NATO meeting.
On Tuesday, NATO reported that an Italian destroyer, Luigi Durand de la Penne, prevented the hijacking of five merchant vessels in the Gulf of Aden. The destroyer positioned itself between the small pirate boats trying to board the cargo ships and used its helicopter to repel them.
Besides the NATO ships, 10 other warships from the United States, India, Russia and Malaysia are patrolling the region at present.
Pirates have attacked 32 vessels and hijacked 12 of them since the NATO operation was launched on Oct. 24. About 50 cargo ships transit daily through the Gulf of Aden, a waterway that links the Indian Ocean with the Suez Canal and the Mediterranean Sea.