Passengers can now book any one of 50 flights per week to six destinations across Canada.
The destinations now include Montreal, Quebec City, Vancouver and Halifax as well as existing services to Toronto and Calgary.
Air Transat is operating three weekly flights to Montreal with flights taking place every day from June as well as a once-a-week service to Quebec City.
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This is the first time UK passengers have been able to book a direct scheduled service to Quebec City.
Air Transat has also increased its flights to Toronto, making it a daily service.
It plans to operate two flights a day from late June, complimenting the daily operation WestJet runs from Gatwick.
WestJet will also be operating six flights a week to Vancouver and in June will increase the schedule to one flight a day.
The carrier will operate four flights a week to Halifax, increasing to daily flights from mid-July.
It will also offer a three times weekly service to Calgary, rising to five per week from mid-June.
Stephanie Wear, vice president of aviation development, Gatwick Airport, said: “With so many people in the UK having close connections with Canada, we are delighted to be able to offer Gatwick passengers such easy and widespread access to fantastic destinations across the country.
“It’s really exciting to have so many more opportunities to visit Canada from Gatwick. It’s also great news for those wishing to see family and friends or conduct business across the Atlantic.”
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