The federal police arrested the group last weekend at Montreal’s international airport and their passports have been withdrawn.
Charges have not been filed and the families and relatives of the 10 people are being interviewed, police said.
The arrests come months after five boys and two girls from the Montreal area left the country and apparently joined IS.
Another teen was arrested in March for aiming to join the IS group.
IS known for its brutality in the swathes of territory it controls in Syria and Iraq. The group’s radical ideology has inspired thousands of people to join IS or try to send it support.