The $82.5-million pedestrian tunnel to Toronto's Billy Bishop airport is expected to open in late July.

Ports Toronto said the project -- which has been under construction for more than three years -- was issued a "substantial completion" certificate on May 29.

"The Ports Toronto team is pleased to announce this significant milestone," the agency's chair, Mark McQueen, said in a statement Monday.

"The tunnel will facilitate business travel, tourism and trade in our city and our strong financial performance has provided the means to invest in this innovative infrastructure project. First announced in 1935, the tunnel is now closer than ever."

Once completed, the pedestrian tunnel will link the island airport to the mainland, meaning travellers will no longer have to wait for a ferry to catch their flight. The tunnel will be outfitted with four moving sidewalks travelling at approximately 2.3 kilometers per hour.

The tunnel will also have elevators on the mainland side that will descend 30 metres down into the tunnel. It will take less than six minutes to travel across the tunnel, which leads to the airport's check-in area.