The 2021 U Sports football season began on August 28, 2021 with the Sherbrooke Vert et Or hosting the Montreal Carabins in Sherbrooke, Quebec. The Atlantic University Sport conference began play on September 17, 2021 and ten Ontario University Athletics teams opened their seasons on September 18, 2021. The Canada West conference began their regular season last with all six teams playing on September 25, 2021. Due to the COVID-19 pandemic in Canada, all conferences except the RSEQ played six regular season games while the RSEQ played eight.