The vessel actually crossed the canal September 4 with a load of steel products from the Pacific to the Atlantic but the authority announced the news only Monday.
Work began a year ago to enlarge the canal by constructing a third set of locks to ensure that today's supersize container ships, cruise liners, and oil tankers—many of which are too wide for the canal—will be able to navigate the waterway in the future.
The cost of the work has been put at some $5.2 billion, and should be complete by August 2014, a century after the canal's inauguration.
Since then a million ships have crossed the 80-kilometer (50-mile) canal, through which five percent of the world's trade crosses every year.
The third set of locks, parallel to the existing two, would accommodate massive vessels 366 meters (1,200 feet) in length, 49 meters (160 feet) wide, and with a 15-meter (50-foot) draft.