The cruise, part of the Navy's campaign to recruit sailors, will send the Antrim to 21 ports over three months.
The IRA threat followed three bomb attacks on British army married quarters in the past month _ one on the outskirts of Londonderry, one at Lisburn where the army is headquartered, and one at Antrim.
More than 120 people were evacuated from their homes in the County Antrim resort of Portrush on Friday after a suspected booby-trap bomb was found under a policeman's car.