Metro Vancouver's new rapid-transit Canada Line will open early, it was announced Tuesday. (CBC)

Vancouver's newest addition to the SkyTrain system, the Canada Line, will officially begin service on Monday, Aug. 17, more than three months earlier than originally scheduled and with a special treat for transit riders.

In announcing the early opening, Canada Line spokesperson Alan Dever said passengers will ride for free on the first day.

But Dever warned that anyone hoping to take advantage of the freebie should be ready to wait.

"We're hoping people will be patient and to expect fairly large crowds. It is a work day in the middle of summer, but we know there's a tremendous interest in the line in the community so we are anticipating fairly large crowds that day," Dever told CBC News Tuesday.

The line links downtown Vancouver to the region's international airport in Richmond, B.C., a trip expected to take about 25 minutes, one way.

The Canada Line cost a reported $1.9 billion to build.

Construction began in 2005 and was scheduled to be finished by October 2009.

The project was highly controversial for its disruptive construction methods, which blocked access to hundreds of retail businesses for years.