The move follows a shift from Canadian health officials who, at the start of the pandemic, questioned the benefits of widespread mask wearing and then later suggested it may help stop the spread of COVID-19.
However, there's still much debate on the effectiveness of the general public wearing face masks, due to a lack of scientific data and concerns over people wearing them improperly. As a result, not all shoppers will buy into the idea of donning face masks.
On Monday, T&T Supermarket chain mandated that shoppers join its employees in wearing face coverings in the store. The Asian grocery chain, which is owned by Loblaws, has locations in Ontario, B.C. and Alberta.
"We believe wearing a face mask or face covering can help to prevent the spread of COVID-19," said T&T CEO Tina Lee in a statement to CBC News.
She said any type of material covering both the nose and mouth will suffice, but "pulling up your jacket collar to cover your mouth doesn't count."
Customers who show up without a mask can buy a disposable one at T&T for $1 with the profits going to a Loblaws-run children's charity.
On May 4, Toronto-based grocer Longo's became the first Canadian retail chain to mandate that customers wear a facial covering; its workers have had to wear one since mid-April.
"We will never stop short of doing what is necessary to keep our team members and guests safe," said CEO Anthony Longo, in a statement.
Like at T&T, Longo's customers can buy a disposable mask for $1 with the profits going to local food banks. Accommodations will be made for customers who can't wear a mask for health or other reasons, said Longo.