What can a coach challenge in the CFL?

Coaches challenge a ruling by throwing a challenge flag. The 2026 Official Playing Rules list these coach challengeable aspects:

• the full list of standard reviewable aspects (scores, possession, touching of the ball, ball spots and down with contact, administrative rulings such as the clock, onside on kicked balls, forward or backward passes, passes touched or completed behind the line of scrimmage, plus the penalty-related items in that list)
• whether a no-yards infraction took place
• whether an offensive or defensive pass interference infraction took place
• whether a penalty for blocking downfield by an eligible receiver took place
• whether a called illegal block on a kick play took place
• whether an infraction for roughing the passer or roughing the kicker took place (for replay, roughing the passer includes any act of unnecessary roughness committed on a designated quarterback behind the line of scrimmage)
• whether the quarterback was tripped behind the line of scrimmage

Number of challenges: each team has 1 challenge. If it is successful, the team keeps it to use later in the game. A challenge is successful if any ruling made on the field is deemed incorrect and changed with favourable results to the team that challenged.

Cost: in regulation time a team needs a timeout to challenge, and an unsuccessful challenge costs the team a timeout. In overtime a team does not need a timeout to challenge, and an unsuccessful challenge does not cost one.