In a news release on Monday, the airline said it is adding flights from Gander to Halifax and Toronto this summer.
The seasonal service to Toronto will begin in early May, and the Halifax connection begins in July.
Gander was one of two new destinations that the airline added on Monday, with the other being Houston, Tex.
WestJet executive vice-president Bob Cummings said the move back to Gander is the latest example of how the airline is expanding.
"Houston and Gander will connect more people, more often, to established and emerging energy markets, and we continue to improve service for our growing number of business travellers," he said.
WestJet left Gander a decade ago after using the airport for a couple of years.- WestJet to drop service to Gander
The airline said it will also be adding more flights in and out of St. John's and Deer Lake.