The agreement was announced just minutes after a key overnight deadline lapsed that would have seen hundreds of flights started to be cancelled over the coming days.
"Air Canada has reached a tentative, four-year collective agreement with the Air Line Pilots Association (ALPA), representing more than 5,200 pilots at Air Canada and Air Canada Rouge," the airline said in a statement.
The two sides had been in talks for 15 months.
This past week, groups representing more than 200,000 businesses across Canada urged the government to intervene, but Prime Minister Justin Trudeau refused, while impressing on both sides that "millions of Canadians (were) counting on everyone to get this resolved."
Both sides would have been in a position at midnight Sunday (0400 GMT) to issue a 72-hour notice of a worker strike or lockout by the airline, which was expected to trigger a phased shutdown of Air Canada's operations and a full stoppage as early as Wednesday.
Air Canada said the new agreement "recognizes the contributions and professionalism" of its pilots, but did not provide any details on the terms, pending its ratification by union members.
The union, which had been pushing for a significant wage bump to close a pay gap with the pilots' American counterparts, said the deal provides "an additional Can$1.9 billion ($1.4 billion) of value for Air Canada pilots over the course of the agreement."
Also, "progress was made on several key issues including compensation, retirement, and work rule," it said.
Air Canada flies to 47 countries and carries an average of 110,000 passengers a day on its 670 flights.
