The product hit retail outlets in Ontario last week and was to ship throughout Canada by the end of the week, said Molson Business Director Sean Shannon.
National print and outdoor campaigns broke Feb. 8, with TV and radio also hitting the airwaves this month.
MacLaren McCann in Toronto and Marketel in Montreal handle Ultra in the English and French markets, respectively.
Robust, fuller-flavor beers make up between 2% and 3% of beer sales in Canada, Mr. Shannon said, but Molson expects that share to grow.
"We think there's a consumer trend," he said.
Molson says its share of Canada's roughly $3 billion domestic beer market was 47.8% for the nine months ended Jan. 1, down from 48.3% the previous year.
Under a restructuring last November, Molson created three regional units to better respond to changing markets and local trends.